List Count

[Oscar Benjamin]

On 23 April 2013 21:00, Terry Jan Reedy <tjreedy at udel.edu> wrote:
>
> That said, I do see that tuple/list.index have had start, stop paramaters
> added, so doing the same for .count is conceivable.

Are those new? I don't remember them not being there.

You need the start/stop parameters to be able to use index for finding
all occurrences of an item rather than just the first:

def indices(value, sequence):
    i = -1
    while True:
        try:
            i = sequence.index(value, i + 1)
        except ValueError:
            return
        yield i

I thought this was a common use case for .index() and that if the
interface had been designed more recently then it might have just been
an .indices() method that returned an iterator.


Oscar