Replace slice in list comperhensions

[fstefanov]

Is there a better way of replacing [-2] position which is == '1' with '2'.

numbers = ['10237310', '10230010']
newlist = [b[0:-2] + '2' + b[-1] for b in numbers if b[-2] == '1']
['10237320', '10230020']

[ineedastupidusername]

This might be a little faster (''.join() is faster than + for strings I think):
newlist=[''.join((b[0:-2],'2',b[-1])) for b in numbers if b[-2]=='1']
Strings are immutable, so you can convert to list('10237320') of string characters (or convert each character to an integer) to make more editable in general if needed.

[fstefanov]

This might be a little faster (''.join() is faster than + for strings I think):
newlist=[''.join((b[0:-2],'2',b[-1])) for b in numbers if b[-2]=='1']
Strings are immutable, so you can convert to list('10237320') of string characters (or convert each character to an integer) to make more editable in general if needed.

You right maybe this one:

newlist = [int(b) + 10 for b in numbers if b[-2] == '1']