I have a python script that creates a list of lists like so:
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.
I've been trying to figure out how to use the cmp() in a list sort
method and I have failed to understand.
Please help.

Quoting Alan G <alan.gauld (AT) freenet (DOT) 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.

you can use Python's own logic to help

def cmplists(lst1,lst2):
return cmp(lst1[2],lst2[2])

Now you can sort Quant by passing your function into sort

Note that in Python2.4+, you can use key= instead:

def sortKey(lst):
return lst[2]
Quant.sort(key=sortKey)

This is more effient than specifying a different comparison function, because
the key function is only called once for each element.