[EMAIL PROTECTED] wrote:
> hi
> I have a file with columns delimited by '~' like this:
>
> 1SOME STRING ~ABC~12311232432D~20060401~00000000
> 2SOME STRING ~DEF~13534534543C~20060401~00000000
> 3SOME STRING ~ACD~14353453554G~20060401~00000000
>
> .....
>
> What is the pythonic way to sort this type of structured text file?
> Say i want to sort by 2nd column , ie ABC, ACD,DEF ? so that it becomes
>
> 1SOME STRING ~ABC~12311232432D~20060401~00000000
> 3SOME STRING ~ACD~14353453554G~20060401~00000000
> 2SOME STRING ~DEF~13534534543C~20060401~00000000
> ?
> I know for a start, that i have to split on '~', then append all the
> second columns into a list, then sort the list using sort(), but i am
> stuck with how to get the rest of the corresponding columns after the
> sort....
In Python 2.4 and up, you can use the key= keyword to list.sort(). E.g.
In [2]: text = """1SOME STRING ~ABC~12311232432D~20060401~00000000
...: 2SOME STRING ~DEF~13534534543C~20060401~00000000
...: 3SOME STRING ~ACD~14353453554G~20060401~00000000"""
In [3]: lines = text.split('\n')
In [4]: lines
Out[4]:
['1SOME STRING ~ABC~12311232432D~20060401~00000000',
'2SOME STRING ~DEF~13534534543C~20060401~00000000',
'3SOME STRING ~ACD~14353453554G~20060401~00000000']
In [5]: lines.sort(key=lambda x: x.split('~')[1])
In [6]: lines
Out[6]:
['1SOME STRING ~ABC~12311232432D~20060401~00000000',
'3SOME STRING ~ACD~14353453554G~20060401~00000000',
'2SOME STRING ~DEF~13534534543C~20060401~00000000']
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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