[Tutor] Sorting a list of lists aka nested lists
jfouhy at paradise.net.nz
Mon Aug 15 01:18:26 CEST 2005
Quoting Alan G <alan.gauld at freenet.co.uk>:
> > Quant.append( [ db_ticker, stock_close, MTD, 0, QTD, 0, YTD, 0,
> > 0, 0 ] )
> > After Quant is created, I want to sort it by MTD. If I use a simple
> > Quant.sort(), I assume its going to sort by 'db_ticker' which is not
> > what I want.
> you need to write your own comparison function.
> Basically it will take two of your lists and return -1,0 or 1.
> Or you can use Python's own logic to help
> def cmplists(lst1,lst2):
> return cmp(lst1,lst2)
> Now you can sort Quant by passing your function into sort...
Note that in Python2.4+, you can use key= instead:
This is more effient than specifying a different comparison function, because
the key function is only called once for each element.
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