extracting numbers from a file, excluding fixed words

[Alex Martelli]

dawenliu <dawenliu at gmail.com> wrote:

> Hi, I have a file with this content:
> xxxxxxx xxxxxxxxxx xxxxx xxxxxxx
> 1
> 0
> 0
> 0
> 1
> 1
> 0
> (many more 1's and 0's to follow)
> yyyyy yyyyyy yyy yyyyyy yyyyy yyy
> 
> The x's and y's are FIXED and known words which I will ignore, such as
> "This is the start of the file" and "This is the end of the file".  The
> digits 1 and 0 have UNKNOWN length.  I want to extract the digits and
> store them in a file.  Any suggestions will be appreciated.

[[warning, untested code...]]

infile = open('infile.txt')
oufile = open('oufile.txt', 'w')
for line in infile:
    if line.strip().isdigit(): oufile.write(line)
oufile.close()
infile.close()


Alex