Advise of programming one of my first programs
Locked
Advise of programming one of my first programs
 
|
Hi guys just wanted to share one of my first programs. Could you please tell me, do I use a right logic ?
It works fine what I wanted to do, but is it writen in the right way? My next step is to make it write the changes of the dictionary on the file :)
## DB tbook = {'goodie':['Christian','Van Eckel','Bruxelles','Forest','02 344 33 33','This is a test note :)'],
'osvaldo':['Osvaldo','Rios','Liege','Centrum','023758832',''], 'ronaldo':['Diego','Aspanda','Brussels','Vorst','03 443 23 23','']}
## Edit selected nickname def edit(): sb = tbook[select] fn = raw_input('New name for ' + sb[0] + ' : ') sb[0] = fn ln = raw_input('New name for ' + sb[1] + ' : ')
sb[1] = ln raw_input('\n\n\nPress <Enter> to return') details() ## Details of nickname def details(): sb = tbook[select]
print 'Nickname: ', select, ' is selected\n' print 'First name:\t', sb[0], '\n' print 'Last name:\t', sb[1], '\n'
print 'Country:\t', sb[2], '\n' print 'City:\t\t', sb[3], '\n' print 'Phone number:\t',sb[4], '\n' print 'Memos:\n'
print sb[5] print '\n\n(E)dit\n\n' print '(B)ack to phonebook list\n\n' menu = raw_input('What you wana do? ')
if menu == 'e': edit() if menu == 'b': listpb() ## Select nickname def selectm():
global select select = raw_input('Type nickname and press <Enter>: ') if select == '': listpb() if select in tbook: details()
else: listpb() ## List all contacts def listpb(): print '_' *45, ' Phonebook ', '_' *45,'\n\n\n' print 'Nick\t\tF.Name\t\tL.Name\t\tCity\t\t\tRegion\t\tTel' print '_' * 105,'\n','\t' * 13 for val in tbook.keys(): print val, '\t\t', tbook[val][0], '\t', tbook[val][1], '\t', tbook[val][2], '\t\t', tbook[val][3], '\t\t', tbook[val][4],'\t\t\n'
print '_'*105,'\n\n' selectm() ## Call list names listpb() Thanks a lot
Anatoli -- http://mail.python.org/mailman/listinfo/python-list |
RE: Advise of programming one of my first programs
|
> Hi guys just wanted to share one of my first programs. Could you please > tell me, do I use a right logic ? > It works fine what I wanted to do, but is it writen in the right way? My > next step is to make it write the changes of the dictionary on the file :) > When you do get that far, you should look at the pickle library. It is amazing how easy it is to store data with Python. > > ## DB > tbook = {'goodie':['Christian','Van Eckel','Bruxelles','Forest','02 344 33 > 33','This is a test note :)'], > 'osvaldo':['Osvaldo','Rios','Liege','Centrum','023758832',''], > 'ronaldo':['Diego','Aspanda','Brussels','Vorst','03 443 23 > 23','']} > > ## Edit selected nickname > def edit(): > sb = tbook[select] > fn = raw_input('New name for ' + sb[0] + ' : ') > sb[0] = fn > ln = raw_input('New name for ' + sb[1] + ' : ') > sb[1] = ln > raw_input('\n\n\nPress <Enter> to return') > details() > > > ## Details of nickname > def details(): > sb = tbook[select] > print 'Nickname: ', select, ' is selected\n' > print 'First name:\t', sb[0], '\n' > print 'Last name:\t', sb[1], '\n' > print 'Country:\t', sb[2], '\n' > print 'City:\t\t', sb[3], '\n' > print 'Phone number:\t',sb[4], '\n' > print 'Memos:\n' > print sb[5] > > print '\n\n(E)dit\n\n' > print '(B)ack to phonebook list\n\n' > menu = raw_input('What you wana do? ') > if menu == 'e': > edit() > if menu == 'b': > listpb() > Minor nitpick, but what if the user types 'B' or 'E' like in your printed menu? > > ## Select nickname > def selectm(): > global select > select = raw_input('Type nickname and press <Enter>: ') > if select == '': > listpb() > if select in tbook: > details() > else: > listpb() Remove all global variables when your program starts to work. Instead pass them as arguments and return them from functions. So do 'details( select )' instead of 'details()' and then in details, you would do edit( select ). > > ## List all contacts > def listpb(): > print '_' *45, ' Phonebook ', '_' *45,'\n\n\n' > > print 'Nick\t\tF.Name\t\tL.Name\t\tCity\t\t\tRegion\t\tTel' > print '_' * 105,'\n','\t' * 13 > for val in tbook.keys(): > print val, '\t\t', tbook[val][0], '\t', tbook[val][1], '\t', > tbook[val][2], '\t\t', tbook[val][3], '\t\t', tbook[val][4],'\t\t\n' > print '_'*105,'\n\n' > selectm() > > ## Call list names > listpb() if __name__ == "__main__": listpb() This way you can import the module and not run it on import; it is useful when you start wanting to reuse functions from a different project. It is better than copy-pasting functions everywhere because when you improve the function all the programs will pick it up. Otherwise you will have to go back to each pasted function and pick it up. A few items I would work to improve: 1. Remove global variables (already mentioned above) 2. You should separate any menu / navigation from your application code. details() should only print the details and not take the next menu choice. You probably want 2 separate menu functions. One that returns a 'select'-ed book and one that returns next choice. This will also help you when you implement my next point. 3. You should also change the structure of your program to loop instead of calling listpb each time you want to restart. It is a much better practice and while it will not affect this program unless you do not exit for 10s or 100s of thousands of details but if you write something that *does* navigate that many times it can crash. Looping is probably your next programming lesson anyway :) 4. This is more of a side note but instead of using \t\t all the time, you would be better off learning to use the string formatting operations. It is a little more effort to learn, but tends to be a lot more reliable on different systems (and with different data trying to be printed) than manually trying to align everything. http://docs.python.org/library/string.html#format-string-syntax Keep on working, you have made a good start and now it is time to refactor (programming equivalent of rewriting an essay) and make everything better! Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 -- This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email. -- http://mail.python.org/mailman/listinfo/python-list |
Re: Advise of programming one of my first programs
|
|
Thank you Ramit for your advice`s. I`m reading a book ( Learning Python, Second Edition ) by Mark Lutz and David Ascher and now I just finished the Basic Function lesson :) I will keep in mind what you have advised me, but will implement it later when I have more experience with the book, because I don`t understand exactly what you mean by doing all dose changes :)
By the way I dont know why your mail was in my junk I just saw it. And here is my last code I did for the phonebook: Thanks ####### CODE ######### fileread = open('myfile.txt','r') tbook = eval(fileread.read()) fileread.close() ## Edit selected nickname def edit():
sb = tbook[select] fn = raw_input('New name for ' + sb[0] + ' : ') sb[0] = fn ln = raw_input('New name for ' + sb[1] + ' : ') sb[1] = ln
filewrite = open('myfile.txt','w') filewrite.write(str(tbook)) filewrite.close() raw_input('\n\n\nPress <Enter> to return') details()
## Details of nickname def details(): sb = tbook[select] print 'Nickname: ', select, ' is selected\n' print 'First name:\t', sb[0], '\n'
print 'Last name:\t', sb[1], '\n' print 'Country:\t', sb[2], '\n' print 'City:\t\t', sb[3], '\n' print 'Phone number:\t',sb[4], '\n'
print 'Memos:\n' print sb[5] print '\n\n(E)dit\n\n' print '(B)ack to phonebook list\n\n' menu = raw_input('What you wana do? ')
if menu == 'e' or 'E': edit() if menu == 'b' or 'B': listpb()
## Select nickname def selectm(): global select select = raw_input('Type nickname and press <Enter>: ') if select == '': listpb()
if select in tbook: details() else: listpb() ## List all contacts def listpb(): print '_' *45, ' Phonebook ', '_' *45,'\n\n\n'
print 'Nick\t\tF.Name\t\tL.Name\t\tCity\t\t\tRegion\t\tTel' print '_' * 105,'\n','\t' * 13 for val in tbook.keys(): print val, '\t\t', tbook[val][0], '\t', tbook[val][1], '\t', tbook[val][2], '\t\t', tbook[val][3], '\t\t', tbook[val][4],'\t\t\n'
print '_'*105,'\n\n' selectm() ## Call list names listpb()
On Tue, Mar 27, 2012 at 12:40 AM, Prasad, Ramit <[hidden email]> wrote:
-- http://mail.python.org/mailman/listinfo/python-list |
RE: Advise of programming one of my first programs
|
|
It is considered polite to post your reply either after the quoted text
or interspersed as I have done below. > By the way I dont know why your mail was in my junk I just saw it. Probably because I only reply back to the list and let the list forward to you. > And here is my last code I did for the phonebook: > Thanks > > ####### CODE ######### > fileread = open('myfile.txt','r') > tbook = eval(fileread.read()) > fileread.close() The use of eval is dangerous if you are not *completely* sure what is being passed in. Try using pickle instead: http://docs.python.org/release/2.5.2/lib/pickle-example.html > Thank you Ramit for your advice`s. I`m reading a book ( Learning Python, > Second Edition ) by Mark Lutz and David Ascher and now I just finished the > Basic Function lesson :) I will keep in mind what you have advised me, but > will implement it later when I have more experience with the book, because > I don`t understand exactly what you mean by doing all dose changes :) Maybe I can help you more by giving you a somewhere to build from. Try building the rest of the program given the new version of listpb below. You will need to read the chapter on Function Arguments (chapter 18?). def listpb(): tbook = load_book() print '_' *45, ' Phonebook ', '_' *45,'\n\n\n' print 'Nick\t\tF.Name\t\tL.Name\t\tCity\t\t\tRegion\t\tTel' print '_' * 105,'\n','\t' * 13 for val in tbook.keys(): print val, '\t\t', tbook[val][0], '\t', tbook[val][1], '\t', tbook[val][2], '\t\t', tbook[val][3], '\t\t', tbook[val][4],'\t\t\n' print '_'*105,'\n\n' while True: choice = get_menu_choice() if choice == 'e' or choice == 'E': book = get_book_to_edit() edit( tbook, book ) elif choice == 'd' or choice == 'D': book = get_book_to_edit() details( tbook, book ) elif choice =='Q' or choice == 'q': break # end loop to exit program else: print 'Selection {0} not understood.'.format( choice ) Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 -- This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email. -- http://mail.python.org/mailman/listinfo/python-list |
Re: Advise of programming one of my first programs
|
On 03/27/12 10:32, Prasad, Ramit wrote:
>> fileread = open('myfile.txt','r') >> tbook = eval(fileread.read()) >> fileread.close() > > The use of eval is dangerous if you are not *completely* sure what is > being passed in. Try using pickle instead: > http://docs.python.org/release/2.5.2/lib/pickle-example.html Or, depending on the use, you might use ast.literal_eval() A cursory glance at the OP's code suggests that this may simply be a dict of values-to-lists of purely literals, so literal_eval() should do the job. -tkc -- http://mail.python.org/mailman/listinfo/python-list |
Re: Advise of programming one of my first programs
|
|
In reply to this post by Prasad, Ramit-2
This was difficult, now I feel more confused it works, but I`m sure its not the way you wanted :)
I`m sure about that I will use pickle nex time
That was hard :) You will need to read the chapter on Function Arguments (chapter 18?). My book is translated in Bulgarian and it is chapter 13 should be the same in the original too. Here is the code now:
def load_book(): load_book = open('c:/Python27/Toli/myfile.txt', 'r') load_book = eval(load_book.read()) return load_book def write_book(tbook):
write_book = open('c:/Python27/Toli/myfile.txt', 'w') write_book.write(str(tbook)) def details(choice): sb = tbook[choice] print 'Nickname: ', choice, ' is selected\n'
print 'First name:\t', sb[0], '\n' print 'Last name:\t', sb[1], '\n' print 'Country:\t', sb[2], '\n' print 'City:\t\t', sb[3], '\n'
print 'Phone number:\t',sb[4], '\n' print 'Memos:\n' print sb[5] print '\n\n(E)dit\n\n' print '(B)ack to phonebook list\n\n'
dmenu(choice) def edit(choice): sb = tbook[choice] fn = raw_input('New name for ' + sb[0] + ' : ') sb[0] = fn ln = raw_input('New name for ' + sb[1] + ' : ')
sb[1] = ln write_book(tbook) ## filewrite = open('myfile.txt','w') ## filewrite.write(str(tbook)) ## filewrite.close() ## raw_input('\n\n\nPress <Enter> to return')
details(choice) def get_menu_choice(): choice = raw_input('input: ') return choice
def listpb(): global tbook tbook = load_book() print '_' *45, ' Phonebook ', '_' *45,'\n\n\n'
print 'Nick\t\tF.Name\t\tL.Name\t\tCity\t\t\tRegion\t\tTel' print '_' * 105,'\n','\t' * 13 for val in tbook.keys(): print val, '\t\t', tbook[val][0], '\t', tbook[val][1], '\t', tbook[val][2], '\t\t', tbook[val][3], '\t\t', tbook[val][4],'\t\t\n'
print '_'*105,'\n\n' mmenu() def mmenu(): while True: choice = get_menu_choice() if choice in tbook:
details(choice) elif choice not in tbook: print choice + 'Not in the book.' mmenu() elif choice =='Q' or choice =='q':
break else: print 'Selection {0} not understood.'.format(choice) ## This is something that I don`t understand yet def dmenu(choice): while True: choicem = get_menu_choice() if choicem == 'e' or choicem == 'E': edit(choice) elif choicem == 'd' or choicem == 'D':
book = get_book_to_edit() details( tbook, book ) elif choicem =='Q' or choicem == 'q': break # end loop to exit program
else: print 'Selection {0} not understood.'.format( choicem ) listpb() -- http://mail.python.org/mailman/listinfo/python-list |
Re: Advise of programming one of my first programs
|
|
In reply to this post by Tim Chase-4
Thanks, but I`m still far from for dose details I thing:)
Regards Anatoli
On Tue, Mar 27, 2012 at 5:53 PM, Tim Chase <[hidden email]> wrote:
-- http://mail.python.org/mailman/listinfo/python-list |
Re: RE: Advise of programming one of my first programs
|
In reply to this post by Prasad, Ramit-2
On 01/-10/-28163 01:59 PM, Prasad, Ramit wrote:
>> ####### CODE ######### >> fileread = open('myfile.txt','r') >> tbook = eval(fileread.read()) >> fileread.close() > > The use of eval is dangerous if you are not *completely* sure what is > being passed in. Try using pickle instead: > http://docs.python.org/release/2.5.2/lib/pickle-example.html Um, at least by my understanding, the use of Pickle is also dangerous if you are not completely sure what is being passed in: Warning: The pickle module is not intended to be secure against erroneous or maliciously constructed data. Never unpickle data received from an untrusted or unauthenticated source. - http://docs.python.org/library/pickle.html Evan -- http://mail.python.org/mailman/listinfo/python-list |
RE: Advise of programming one of my first programs
|
|
In reply to this post by Anatoli Hristov
> def load_book():
> load_book = open('c:/Python27/Toli/myfile.txt', 'r') > load_book = eval(load_book.read()) > return load_book > def write_book(tbook): > write_book = open('c:/Python27/Toli/myfile.txt', 'w') > write_book.write(str(tbook)) > > def details(choice): > sb = tbook[choice] > print 'Nickname: ', choice, ' is selected\n' > print 'First name:\t', sb[0], '\n' > print 'Last name:\t', sb[1], '\n' > print 'Country:\t', sb[2], '\n' > print 'City:\t\t', sb[3], '\n' > print 'Phone number:\t',sb[4], '\n' > print 'Memos:\n' > print sb[5] > print '\n\n(E)dit\n\n' > print '(B)ack to phonebook list\n\n' > dmenu(choice) > > def edit(choice): > sb = tbook[choice] > fn = raw_input('New name for ' + sb[0] + ' : ') > sb[0] = fn > ln = raw_input('New name for ' + sb[1] + ' : ') > sb[1] = ln > write_book(tbook) > ## filewrite = open('myfile.txt','w') > ## filewrite.write(str(tbook)) > ## filewrite.close() > ## raw_input('\n\n\nPress <Enter> to return') > details(choice) > > def get_menu_choice(): > choice = raw_input('input: ') > return choice > > > > def listpb(): > global tbook > tbook = load_book() > print '_' *45, ' Phonebook ', '_' *45,'\n\n\n' > print 'Nick\t\tF.Name\t\tL.Name\t\tCity\t\t\tRegion\t\tTel' > print '_' * 105,'\n','\t' * 13 > for val in tbook.keys(): > print val, '\t\t', tbook[val][0], '\t', tbook[val][1], '\t', > tbook[val][2], '\t\t', tbook[val][3], '\t\t', tbook[val][4],'\t\t\n' > print '_'*105,'\n\n' > mmenu() > > def mmenu(): > while True: > choice = get_menu_choice() > if choice in tbook: > details(choice) > elif choice not in tbook: > print choice + 'Not in the book.' > mmenu() > elif choice =='Q' or choice =='q': > break > else: > print 'Selection {0} not understood.'.format(choice) ## This is > something that I don`t understand yet > > > def dmenu(choice): > while True: > choicem = get_menu_choice() > if choicem == 'e' or choicem == 'E': > edit(choice) > elif choicem == 'd' or choicem == 'D': > book = get_book_to_edit() > details( tbook, book ) > elif choicem =='Q' or choicem == 'q': > break # end loop to exit program > else: > print 'Selection {0} not understood.'.format( choicem ) > > listpb() > This was difficult, now I feel more confused it works, but I`m sure its not > the way you wanted :) You are correct it is not. :) You code is overly complex making it harder to understand. Try and reduce the problem to the least number of tasks you need. >From the Zen of Python, "Simple is better than complex." It is a good programming mentality. 1. function that returns the loaded book def load_book(): load_book = open('c:/Python27/Toli/myfile.txt', 'r') load_book = eval(load_book.read()) return load_book! 2. A system to navigate your program. def mmenu(): # load tbook here while True: choicem = get_menu_choice() if choicem == 'e' or choicem == 'E': book = get_book_name() edit( tbook, book ) elif choicem == 'd' or choicem == 'D': book = get_book_name() details( tbook, book ) elif choicem =='Q' or choicem == 'q': break # end loop to exit program else: print 'Selection {0} not understood.'.format( choicem )I have given you more functions 3. function to write an edited book def write_book(tbook): write_book = open('c:/Python27/Toli/myfile.txt', 'w') write_book.write(str(tbook)) # I think repr would be more accurate than str here. 4. Function to print the entire book def listpb( tbook ): print '_' *45, ' Phonebook ', '_' *45,'\n\n\n' print 'Nick\t\tF.Name\t\tL.Name\t\tCity\t\t\tRegion\t\tTel' print '_' * 105,'\n','\t' * 13 for val in tbook.keys(): print val, '\t\t', tbook[val][0], '\t', tbook[val][1], '\t', tbook[val][2], '\t\t', tbook[val][3], '\t\t', tbook[val][4],'\t\t\n' print '_'*105,'\n\n' 5. Get input from user def get_menu_choice(): choice = raw_input('input: ') return choice 6. A function to get book name from user def get_book_name(tbook): # write this and do not use global 6. A function to print an entry from the book def details( tbook, choice ): # write this, no menu interaction allowed 7. A function to edit an entry from the book def edit( tbook, choice ): # write this, no menu interaction allowed # you can ask the user what you need to change the values I do not think you need any other functions. Now you just need to finsh all the functions and put it all together. Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 -- This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email. -- http://mail.python.org/mailman/listinfo/python-list |
Re: Advise of programming one of my first programs
|
|
In reply to this post by Anatoli Hristov
On 03/27/12 16:53, Anatoli Hristov wrote:
> On Tue, Mar 27, 2012 at 5:53 PM, Tim Chase wrote: >>> On 03/27/12 10:32, Prasad, Ramit wrote: >>>> fileread = open('myfile.txt','r') >>>> tbook = eval(fileread.read()) >>>> fileread.close() >>> >>> >>> The use of eval is dangerous if you are not *completely* sure what is >>> being passed in. Try using pickle instead: >> >> Or, depending on the use, you might use ast.literal_eval() > > Thanks, but I`m still far from for dose details I thing:) [reordered to make the commenting inline instead of top-posted] To make it safer, just change eval(fileread.read()) to ast.literal_eval(fileread.read()) and insert "import ast" at the top of your script. -tkc -- http://mail.python.org/mailman/listinfo/python-list |
Re: RE: Advise of programming one of my first programs
|
In reply to this post by Evan Driscoll-3
On Tue, Mar 27, 2012 at 5:59 PM, Evan Driscoll <[hidden email]> wrote:
>> The use of eval is dangerous if you are not *completely* sure what is >> being passed in. Try using pickle instead: >> http://docs.python.org/release/2.5.2/lib/pickle-example.html > > > Um, at least by my understanding, the use of Pickle is also dangerous if you > are not completely sure what is being passed in: Oh goodness yes. pickle is exactly as unsafe as eval is. Try running this code: from pickle import loads loads("c__builtin__\neval\n(c__builtin__\nraw_input\n(S'py>'\ntRtR.") -- Devin -- http://mail.python.org/mailman/listinfo/python-list |
RE: RE: Advise of programming one of my first programs
|
|
> >> The use of eval is dangerous if you are not *completely* sure what is
> >> being passed in. Try using pickle instead: > >> http://docs.python.org/release/2.5.2/lib/pickle-example.html > > > > > > Um, at least by my understanding, the use of Pickle is also dangerous if > you > > are not completely sure what is being passed in: > > Oh goodness yes. pickle is exactly as unsafe as eval is. Try running this > code: > > from pickle import loads > loads("c__builtin__\neval\n(c__builtin__\nraw_input\n(S'py>'\ntRtR.") It might be as dangerous, but which is more likely to cause problems in real world scenarios? Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 -- This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email. -- http://mail.python.org/mailman/listinfo/python-list |
Re: Advise of programming one of my first programs
|
|
In reply to this post by Prasad, Ramit-2
You are correct it is not. :) You code is overly complex making it harder Complex is better than complicated. :p
With the main navigation menu I will only have the option to select a nickname and when a nickname is selected then it loads Details of the contact and from loaded details I can choice Edit or back to main screen, like I did it the first time, or else I can do it => when 'e' pressed to ask for a nickname and then edit it.
3. function to write an edited book I`m not that far as you already know :) I hope I will learn everything as soon as I can as I`m not capable to read python everyday.
I do not think you need any other functions. Now you just need to finsh all the functions Thanks Anatoli -- http://mail.python.org/mailman/listinfo/python-list |
Re: RE: Advise of programming one of my first programs
|
|
In reply to this post by Prasad, Ramit-2
> > Um, at least by my understanding, the use of Pickle is also dangerous if Guys this is really something that is not that important at this time for me -- http://mail.python.org/mailman/listinfo/python-list |
Re: RE: Advise of programming one of my first programs
|
Thu, Mar 29, 2012 at 9:36 AM, Anatoli Hristov <[hidden email]> wrote:
>> > > Um, at least by my understanding, the use of Pickle is also dangerous >> > > if you are not completely sure what is being passed in: >> > >> > Oh goodness yes. pickle is exactly as unsafe as eval is. Try running >> > this code: >> > >> > from pickle import loads >> > loads("c__builtin__\neval\n(c__builtin__\nraw_input\n(S'py>'\ntRtR.") >> >> It might be as dangerous, but which is more likely to cause problems in >> real world scenarios? > > Guys this is really something that is not that important at this time for > me Maybe not, but it's still worth being aware of. Even if today your strings will never include apostrophes, it's still important to understand the risks of SQL injection and properly escape them before inserting them into an SQL statement. Just docket the information in the back of your mind "Don't use pickle with untrusted data" and move on. :) ChrisA -- http://mail.python.org/mailman/listinfo/python-list |
RE: RE: Advise of programming one of my first programs
|
|
In reply to this post by Anatoli Hristov
From: Anatoli Hristov [mailto:[hidden email]]
>>> > Um, at least by my understanding, the use of Pickle is also dangerous if >Guys this is really something that is not that important at this time for me “My Eyes! The goggles do nothing!” Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 -- This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email. -- http://mail.python.org/mailman/listinfo/python-list |
RE: Advise of programming one of my first programs
|
|
In reply to this post by Anatoli Hristov
>>From the Zen of Python, "Simple is better than complex." It is a good programming mentality. >Complex is better than complicated. :p Absolutely! Too bad your version would be considered the more “complicated” version ;) >With the main navigation menu I will only have the option to select a nickname and when a nickname is selected then it loads Details of the contact and from loaded details I can choice Edit or back to main screen, like I did it the first
time, or else I can do it => when 'e' pressed to ask for a nickname and then edit it. I was trying to simplify it to “guide” you to a more correct solution without feeding you the answer. Maybe I should have given you the explanation first to explain why you should be doing it a different way. Going back to your original program (and your modifications to it), the original menu can cause crashing in more complicated programs and thus is considered a bad style. It was basically using recursion (I will touch on this later) but
without any of the benefits. It was endlessly branching instead of a simple loop. Sort of like the following Menu/submenu example. Menu submenu Menu submenu Menu __ad infinitum__ How does this matter? Let’s look at some simpler code below. print ‘start’ function_a() # a function is called print ‘a’ # code inside the function print ‘b’ # code inside the function a = ‘ something ‘ print a function_b() # another function call print ‘c’ # code inside a different function print ‘d’ # code inside a different function print ‘end’ Let us pretend we are the computer who executes one line at a time and so basically goes through a list of commands. The list we are going to execute is the following: print ‘start’ function_a() print ‘a’ print ‘b’ a = ‘ something ‘ print a function_b() print ‘c’ print ‘d’ print ‘end’ How does the computer know to execute “a = ‘ something ‘” after “print ‘b’”? It does it by storing the location where it was before it proceeds to the function call. That way when the end of the function is reached it returns to the previous
spot. In essence: print ‘start’ function_a() __store this location so I can come back__ print ‘a’ print ‘b’ __return to previous location__ a = ‘ something ‘ print a function_b() __store this location so I can come back__ print ‘c’ print ‘b’ __return to previous location__ print ‘end’ Now what happens if “function_a” calls “function_a”? By the way, the term for this type of call is recursion. print ‘start’ function_a() __store this location so I can come back__
print ‘a’
print ‘b’ function_a() __store this location so I can come back__
print ‘a’
print ‘b’
function_a() __store this location so I can come back__
print ‘a’ print ‘b’ function_a() __store this location so I can come back__ print ‘a’ print ‘b’ function_a() __store this location so I can come back__ print ‘a’ print ‘b’ function_a() __store this location so I can come back__ *until the program ends* Now each __store__ action takes up memory and when the computer (or your program) runs out of memory your computer crashes. Your application is trivial and more likely to be ended by the user instead of going through the tens of thousands
if not hundreds of thousands that Python will let you take, but it is a bad practice and a habit to avoid. A real world program would use more memory and quit even faster than yours. Recursion has its place in programming, but not in this case! What you need
is a simple loop. That is why I provided you with the menu I did. The following menu sounds like what you want; there were a couple different ways I could have done this. In this version, if you type anything when asked for a menu choice that is not ‘e’ or ‘q’, the program will automatically ask you
for the next book choice. def mmenu(): # load tbook here while True: book = get_book_choice() details( tbook, book ) choicem = get_menu_choice() if choicem == 'e' or choicem == 'E': edit( tbook, book ) # save tbook here elif choicem =='Q' or choicem == 'q': break # end loop to exit program Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 -- This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email. -- http://mail.python.org/mailman/listinfo/python-list |
Re: Advise of programming one of my first programs
|
|
I`m sure about that, but I`am also sure that every beginner passed true that way.
Just before I read you mail I`ve finished my book ver. 12 with this code, ver 13 will have all the modifications and all remarks I have from you: import ast
fname = 0 lname = 1 country = 2 city = 3 tel = 4 notes = 5 ## Read data from file def load_book(): load_book = open('c:/Python27/Toli/myfile.txt', 'r')
load_book = ast.literal_eval(load_book.read()) return load_book ## Write data to file def write_book(tbook): write_book = open('c:/Python27/Toli/myfile.txt', 'w')
write_book.write(repr(tbook)) ## Menu choice input def get_menu_choice(): choice = raw_input('input: ')
return choice ## List data contacts def listpb(): tbook = load_book() print '_' *45, ' Phonebook ', '_' *45,'\n\n\n'
print 'Nick\t\tF.Name\t\tL.Name\t\tCountry\t\t\tCity\t\tTel' print '_' * 105,'\n','\t' * 13 for val in tbook.keys(): print val, '\t\t', tbook[val][fname], '\t', tbook[val][lname], '\t', tbook[val][country], '\t\t', tbook[val][city], '\t\t', tbook[val][tel],'\t\t\n'
print '_'*105,'\n\n\n\n' print 'Type nickname and press <Enter> or type <Q> to exit.\n\n\n' mmenu(tbook) ## Main menu
def mmenu(tbook): while True: choice = get_menu_choice() if choice in tbook: details(choice,tbook) elif choice == 'q' or choice == 'Q':
break else: print 'Selection {0} not understood.'.format(choice) ## Details menu def dmenu(choice, tbook):
while True: choicem = get_menu_choice() if choicem == 'e' or choicem == 'E': edit(choice, tbook) elif choicem == 'b' or choicem == 'B':
listpb() elif choicem =='Q' or choicem == 'q': break # end loop to exit program else: print 'Selection {0} not understood.'.format( choicem )
## Contact details def details(choice, tbook): sb = tbook[choice] print 'Nickname: ', choice, ' is selected\n'
print 'First name:\t', sb[fname], '\n' print 'Last name:\t', sb[lname], '\n' print 'Country:\t', sb[country], '\n' print 'City:\t\t', sb[city], '\n'
print 'Phone number:\t',sb[tel], '\n' print 'Memos:\n' print sb[notes] print '\n\n(E)dit\n\n' print '(B)ack to phonebook list\n\n'
dmenu(choice, tbook) ## Edit contact def edit(choice, tbook): sb = tbook[choice] fn = raw_input('New name for ' + sb[fname] + ' : ')
if fn == '': pass else: sb[fname] = fn ln = raw_input('New name for ' + sb[lname] + ' : ') if ln == '':
pass else: sb[lname] = ln write_book(tbook) details(choice, tbook) listpb()
-- http://mail.python.org/mailman/listinfo/python-list |
Re: Advise of programming one of my first programs
|
|
Ramit,
This seems to be more logic now "I hope" :) ######################################### import ast fname = 0 lname = 1 country = 2
city = 3 tel = 4 notes = 5 ## Read data from file def load_book(): load_book = open('c:/Python27/Toli/myfile.txt', 'r')
load_book = ast.literal_eval(load_book.read()) return load_book ## Write data to file def write_book(tbook): write_book = open('c:/Python27/Toli/myfile.txt', 'w')
write_book.write(repr(tbook)) ## Menu choice input def get_menu_choice(text): choice = raw_input(text)
return choice ## List data contacts def listpb(): ##tbook = load_book() print '_' *45, ' Phonebook ', '_' *45,'\n\n\n'
print 'Nick\t\tF.Name\t\tL.Name\t\tCountry\t\t\tCity\t\tTel' print '_' * 105,'\n','\t' * 13 for val in tbook.keys(): print val, '\t\t', tbook[val][fname], '\t', tbook[val][lname], '\t', tbook[val][country], '\t\t', tbook[val][city], '\t\t', tbook[val][tel],'\t\t\n'
print '_'*105,'\n\n\n\n' print 'Type nickname and press <Enter> or type <Q> to exit.\n\n\n' ## Main menu def mmenu(tbook):
listpb() while True: text = 'Type your option: ' choice = get_menu_choice(text) if choice == 'e' or choice == 'E':
text = 'Type nickname and press <Enter> to edit: ' choicen = get_menu_choice(text) if choicen in tbook: edit(choicen, tbook)
elif choice == 'b' or choice == 'B': listpb() elif choice == 'd' or choice == 'D': text = 'Type nickname and press <Enter> for details: '
choicen = get_menu_choice(text) if choicen in tbook: details(choicen, tbook) elif choice == 'q' or choice == 'Q':
break else: print 'Selection {0} not understood.'.format(choice) ## Contact details def details(choicen, tbook):
sb = tbook[choicen] print 'Nickname: ', choicen, ' is selected\n' print 'First name:\t', sb[fname], '\n' print 'Last name:\t', sb[lname], '\n'
print 'Country:\t', sb[country], '\n' print 'City:\t\t', sb[city], '\n' print 'Phone number:\t',sb[tel], '\n' print 'Memos:\n'
print sb[notes] print '\n\n(E)dit\n\n' print '(B)ack to phonebook list\n\n' ## Edit contact def edit(choicen, tbook):
sb = tbook[choicen] fn = raw_input('New name for ' + sb[fname] + ' : ') if fn == '': pass else: sb[fname] = fn
ln = raw_input('New name for ' + sb[lname] + ' : ') if ln == '': pass else: sb[lname] = ln write_book(tbook)
details(choicen, tbook) tbook = load_book() mmenu(tbook) ####################################### What you thing?
Regards Anatoli
-- http://mail.python.org/mailman/listinfo/python-list |
RE: Advise of programming one of my first programs
|
|
> Ramit,
> > This seems to be more logic now "I hope" :) > ######################################### > import ast > fname = 0 > lname = 1 > country = 2 > city = 3 > tel = 4 > notes = 5 > > ## Read data from file > > def load_book(): > load_book = open('c:/Python27/Toli/myfile.txt', 'r') > load_book = ast.literal_eval(load_book.read()) > return load_book > > ## Write data to file > > def write_book(tbook): > write_book = open('c:/Python27/Toli/myfile.txt', 'w') > write_book.write(repr(tbook)) Either use write_book.close() or a context manager instead. I suggest the context manager approach but it only works on Python 2.6+ Otherwise, there is a chance that the file might not get written out. > > ## Menu choice input > > def get_menu_choice(text): > choice = raw_input(text) > return choice > > ## List data contacts > > def listpb(): > ##tbook = load_book() > print '_' *45, ' Phonebook ', '_' *45,'\n\n\n' > print 'Nick\t\tF.Name\t\tL.Name\t\tCountry\t\t\tCity\t\tTel' > print '_' * 105,'\n','\t' * 13 tbook should be passed in. This is currently using the global variable which is generally discouraged. > for val in tbook.keys(): > print val, '\t\t', tbook[val][fname], '\t', tbook[val][lname], > '\t', tbook[val][country], '\t\t', tbook[val][city], '\t\t', > tbook[val][tel],'\t\t\n' > print '_'*105,'\n\n\n\n' The following looks like menu choices and should instead be printed along with the menu text. > print 'Type nickname and press <Enter> or type <Q> to exit.\n\n\n' > > ## Main menu > > def mmenu(tbook): > listpb() > while True: > text = 'Type your option: ' > choice = get_menu_choice(text) > if choice == 'e' or choice == 'E': > text = 'Type nickname and press <Enter> to edit: ' > choicen = get_menu_choice(text) > if choicen in tbook: > edit(choicen, tbook) > elif choice == 'b' or choice == 'B': > listpb() > elif choice == 'd' or choice == 'D': > text = 'Type nickname and press <Enter> for details: ' > choicen = get_menu_choice(text) > if choicen in tbook: > details(choicen, tbook) > elif choice == 'q' or choice == 'Q': > break > else: > print 'Selection {0} not understood.'.format(choice) > > ## Contact details > > def details(choicen, tbook): > sb = tbook[choicen] > print 'Nickname: ', choicen, ' is selected\n' > print 'First name:\t', sb[fname], '\n' > print 'Last name:\t', sb[lname], '\n' > print 'Country:\t', sb[country], '\n' > print 'City:\t\t', sb[city], '\n' > print 'Phone number:\t',sb[tel], '\n' > print 'Memos:\n' > print sb[notes] Again, the following menu options should be printed where you call get_menu_choice. > print '\n\n(E)dit\n\n' > print '(B)ack to phonebook list\n\n' > > ## Edit contact > > def edit(choicen, tbook): > sb = tbook[choicen] > fn = raw_input('New name for ' + sb[fname] + ' : ') > if fn == '': > pass > else: > sb[fname] = fn > ln = raw_input('New name for ' + sb[lname] + ' : ') > if ln == '': > pass > else: > sb[lname] = ln > write_book(tbook) > details(choicen, tbook) > tbook = load_book() > mmenu(tbook) > > ####################################### > > What you thing? > > Regards > > Anatoli Looks better. Instead of having global variables (fname, lname, tel) why not just use a string in 'last_name', 'first_name', and 'telephone #'? That would be more self explanatory when looking at the data file and reading the code. References like sb[lname] would become sb['last_name'] Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 -- This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email. -- http://mail.python.org/mailman/listinfo/python-list |
| Powered by Nabble | Edit this page |