value error

[Jeremiah Dodds]

On Thu, Apr 23, 2009 at 3:59 PM, Francesco Pietra <chiendarret at gmail.com>wrote:

> hi:
> with script
>
> data = open('134-176_rectified_edited.pdb', 'r')
> outp = open('134-176_renumbered.pdb', 'w')
>
> for L in data:
>   if L[3] == 'M':
>     L = L[:24] + "%4d" % (int(L[24-28])+133) + L[28:]
>   outp.write(L)
>
>
> i wanted to modify lines of the type:
> ATOM      1 HH31 ACE     1       1.573   1.961   0.769  1.00  0.00
>   H
>
> to add 133 to column 25, getting 134 there, and so on for next lines 2
> -> 135, 3 -> 136, etc.
>
>
> i must have heavily messed things because the file was not even read:
>
> $ python renumber.py 134-176_rectified.pdb
> Traceback (most recent call last):
>  File "renumber.py", line 6, in <module>
>    L = L[:24] + "%4d" % (int(L[24-28])+133) + L[28:]
> ValueError: invalid literal for int() with base 10: ''
>
>
>
> thanks for having an expert look
>
> chiendarret
> --
> http://mail.python.org/mailman/listinfo/python-list
>


I wrote this function the other day for something similar I needed to do,
you may find it useful:

def chunk_line(line, steps):
    """Return a list of chunks from a string, with sizes as specified by the
    list steps.

    >>> line = '1121231234'
    >>> steps = [1,2,3,4]
    >>> chunk_line(line, steps)
    ['1', '12', '123', '1234']
    """
    result = []
    for step in steps:
        result.append(line[:step])
        line = line[step:]
    return result
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