List Comprehension - Python

Question

I'm trying iterate over lists in Python, but can't do it in an economic and pythonic way.

I can do in one dimension list:

api_time = ['hour', 'time']

text = 'What time is it?'
request = [r for r in api_time if r in text]

This outputs 'time', which is correct.

But when I start using two dimension list, I can't do it in one sentence.

api_time = ['hour', 'time']
api_weather = ['clime', 'rain']

apis = [api_time, api_weather]

How can I check this in one sentence?

Are you asking how to add `list`s? `apis = api_time + api_weather` ? — Chris_Rands, Aug 04 '17 at 12:45
Can you give an example of what you want the output to look like? — glibdud, Aug 04 '17 at 12:46
Or https://stackoverflow.com/questions/1663807/how-can-i-iterate-through-two-lists-in-parallel — OneCricketeer, Aug 04 '17 at 12:47
`request = [r for r in (api_time + api_weather) if r in text]` — Donat Pants, Aug 04 '17 at 12:47
Dupe seems a little premature to me. I'm not convinced he wants to flatten the lists. He may need to know which parts of each individual list match. — glibdud, Aug 04 '17 at 12:58

Eric Duminil · Accepted Answer · 2017-08-04T12:50:55.660

2

You can use a double list comprehension:

>>> api_time = ['hour', 'time']
>>> api_weather = ['clime', 'rain']
>>>
>>> apis = [api_time, api_weather]
>>> text = 'What time is it?'
>>> [r for api in apis for r in api if r in text]
['time']

Or a simple list addition instead of nested lists:

>>> [r for r in api_time + api_weather if r in text]
['time']

edited Aug 04 '17 at 12:50

answered Aug 04 '17 at 12:47

Eric Duminil

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Probably would have been a better option to help close it as a dupe. – idjaw Aug 04 '17 at 12:48
I think their mistake was making nested `list`s in the first place, no need to flatten them if they just concatenate the lists @idjaw – Chris_Rands Aug 04 '17 at 12:48
This is what I wanted, thank you. This is faster than two nested for loops? – Denis Callau Aug 04 '17 at 12:50
@Chris_Rands Right. Are you saying that maybe it is not a dupe, but instead provide a different solution? – idjaw Aug 04 '17 at 12:50
@idjaw I'm saying what Eric just added in the edit, I'm not sure it's worth re-opening though, there is another dupe somewhere no doubt – Chris_Rands Aug 04 '17 at 12:51
The list addition is not viable cause the objective is increase the number of apis. – Denis Callau Aug 04 '17 at 12:51

List Comprehension - Python

1 Answers1