how to avoid leading white spaces

[rurpy at yahoo.com]

On Jun 1, 11:11 am, Chris Rebert <c... at rebertia.com> wrote:
> On Wed, Jun 1, 2011 at 12:31 AM, rakesh kumar
> > Hi
> >
> > i have a file which contains data
> >
> > //ACCDJ         EXEC DB2UNLDC,DFLID=&DFLID,PARMLIB=&PARMLIB,
> > //         UNLDSYST=&UNLDSYST,DATABAS=MBQV1D0A,TABLE='ACCDJ       '
> > //ACCT          EXEC DB2UNLDC,DFLID=&DFLID,PARMLIB=&PARMLIB,
> > //         UNLDSYST=&UNLDSYST,DATABAS=MBQV1D0A,TABLE='ACCT        '
> > //ACCUM         EXEC DB2UNLDC,DFLID=&DFLID,PARMLIB=&PARMLIB,
> > //         UNLDSYST=&UNLDSYST,DATABAS=MBQV1D0A,TABLE='ACCUM       '
> > //ACCUM1        EXEC DB2UNLDC,DFLID=&DFLID,PARMLIB=&PARMLIB,
> > //         UNLDSYST=&UNLDSYST,DATABAS=MBQV1D0A,TABLE='ACCUM1      '
> >
> > i want to cut the white spaces which are in between single quotes after TABLE=.
> >
> > for example :
> >                                'ACCT[spaces] '
> >                                'ACCUM           '
> >                                'ACCUM1         '
> > the above is the output of another python script but its having a leading spaces.
>
> Er, you mean trailing spaces. Since this is easy enough to be
> homework, I will only give an outline:
>
> 1. Use str.index() and str.rindex() to find the positions of the
> starting and ending single-quotes in the line.
> 2. Use slicing to extract the inside of the quoted string.
> 3. Use str.rstrip() to remove the trailing spaces from the extracted string.
> 4. Use slicing and concatenation to join together the rest of the line
> with the now-stripped inner string.
>
> Relevant docs:http://docs.python.org/library/stdtypes.html#string-methods

For some odd reason (perhaps because they are used a lot in Perl),
this groups seems to have a great aversion to regular expressions.
Too bad because this is a typical problem where their use is the
best solution.

    import re
    f = open ("your file")
    for line in f:
        fixed = re.sub (r"(TABLE='\S+)\s+'$", r"\1'", line)
        print fixed,

(The above is for Python-2, adjust as needed for Python-3)