Help with code = Extract numerical value to variable

[rurpy at yahoo.com]

On 10/23/2009 05:16 AM, Dave Angel wrote:
> Steve wrote:
>> Sorry I'm not being clear
>>
>> ****Input******
>> sold: 16
>> sold: 20
>> sold: 2
>> sold: 0
>> sold: <storefront>
>> 7
>> 0
>> <storefront>
>> sold
>> null
>>
>> ****Output****
>> 16
>> 20
>> 2
>> 0
>> 0
>> 7
>> 0
>> 0
>> 0
>> 0
>
> Since you're looking for only digits, simply make a string containing
> all characters that aren't digits.
>
> Now, loop through the file and use str.translate() to delete all the
> non-digits from each line, using the above table.
>
> Check if the result is "", and if so, substitute "0".  Done.

delchars = ''.join([chr(i) for i in range (256) if chr(i)<'0' or chr(i)
>'9'])
f = open ('your_input_filename.txt')
for line in f:
    num = line.translate (None, delchars)
    if num == '': num = '0'
    print num

IMO, Python's translate function in unpleasant enough
to use that I might use a regex here, although the
code above is likely faster if you are running this on
large input files.

import re
f = open ("your_input_filename.txt")
for line in f:
    mo = re.search ('\d+', line)
    if mo: print mo.group(0)
    else: print '0'