python using yield from in a function

Question

i have a list like:

list=['2,130.00','2,140.00','2,150.00','2,160.00']

i would like to use a function like

def f(iterable):
    yield from iterable

and applying

float(item.replace(',','')) for item in iterable

at the same time so that

f(list)

returns

[2130.00,2140.00,2150.00,2160.00]

I know

[float(x.replace(',','')) for x in list]

works here but it is to understand how to use yield from in a function and modifying items in the iterable at the same time. Maybe i have to use *args and/or **kwargs in the function but not sure i have and how to.

score 3 · Answer 1 · edited Sep 22 '14 at 11:08

3

yield from is a pass-through; you are delegating to the iterable. Either wrap the iterable in a generator expression to transform elements, or don't use yield from but an explicit loop:

def f(iterable):
    yield from (i.replace(',', '') for i in iterable)

or

def f(iterable):
    for item in iterable:
        yield item.replace(',', '')

edited Sep 22 '14 at 11:08

Pavel Šimerda

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answered Sep 22 '14 at 10:33

Martijn Pieters

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2

thanks so in the end yield from is not very useful in this type of context – addequttorr Sep 22 '14 at 10:42
2

@addequttorr: `yield from` is extremely useful when delegating to other generators. It is not the right tool for transforming the data from another iterable. – Martijn Pieters Sep 22 '14 at 10:46
1

Are there any post documenting this? – addequttorr Sep 22 '14 at 10:48
1

@addequttorr: [Difference between \`yield from foo()\` and \`for x in foo(): yield x\`](http://stackoverflow.com/q/25890604) – Martijn Pieters Sep 22 '14 at 11:09

python using yield from in a function

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