[Tutor] searching data from a list read from a file

[Alan Gauld]

"Lea Parker" <lea-parker at bigpond.com> wrote in 

Peter has pointred you to the answer, here are some 
general comments:

> def main():
> 
>    try:

SDee the recent posts re the scope of try/except handling. 
This is probably a bit too much for a single exception type!

>        # Open file for reading
>        infile = open('charge_accounts.txt', 'r')
> 
>        # Read the contents of the file inot a lsit
>        account_number = infile.readlines()

As a point of style if a variabl;e holds a collection of things 
use the plural form so this would be batter named 
account_numbers

>        #Convert each element into an int
>        index = 0
>        while index != len(account_number):
>            account_number[index] = int(account_number[index])
>            index += 1

This could be done using map():

         account_number = map(int,account_number)

or using a list comprehension:

         account_number = [int(num) for num in account_number]

or even using a 'for' loop:

       for index, num in enumerate(account_number):
              account_number[index] = int(num)

Any of which would be better than the while style.
Use 'while' for cases where you don't know in advance 
how many items you need to proccess.

>        # Print the contents of the list
>        print account_number

>        #Get an account number to search for
>        search = raw_input('Enter a charge account number: ')
> 
>        #Determine whether the product number is in thelist
>        if search in account_number:

As Peter says, check the types here...

>            print search, 'charge account number is VALID'
>        else:
>            print search, 'charge account number is INVALID'
>        infile.close()
>    except ValueError:
>        print 'file open error message'

HTH,


-- 
Alan Gauld
Author of the Learn to Program web site
http://www.alan-g.me.uk/