where is the awk to python translator program

Skip Montanaro skip at pobox.com
Sat Jul 26 08:25:45 CEST 2003


    Dan> An old dog can't learn new tricks, so where's the a2py awk to python
    Dan> translator?  Perl has a2p.

Sorry, Python doesn't have such a beast.  There's never been enough demand.

    Dan> E.g. today I wonder how to do '{print $1}', well with a2p I know
    Dan> how to do it in perl, but with python I am supposed to hunker down
    Dan> with the manuals.

Python doesn't have the implicit looping and splitting into fields that awk
has, so you need to loop over the input and split the fields yourself:

    import sys
    for line in sys.stdin:
        print line.split()[0]   # == '{print $1}'

There's also no global field separator variable.  Suppose I wanted to print
the first field in each row of my passwd file.  The split() method, when
called as above with no arguments, will split the string on any runs of
whitespace.  If given a string parameter it will split the string on that
string.  Here's some input and output pasted from an interactive session:

    >>> for line in file("/etc/passwd"):
    ...     print line.split(":")[0]
    ... 
    root
    bin
    daemon
    adm
    lp
    ... and so on ...

Obviously, Python is not as concise as awk for the sorts of things awk is
good at, but then Python is good for a lot more things than awk is. ;-)

Skip





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