What is this python syntax? Repeatedly call a function with iterable and package return values as array

Asked Mar 08 '17 at 15:08

Active Mar 08 '17 at 15:08

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This line is found in the python docs:

 future_to_url = {executor.submit(load_url, url, 60): url for url in URLS}

It seems to repeatedly call a function (submit) using arguments from a list (URLS)

What is the name for this syntax (idiom?).

Is future_to_url a list?

asked Mar 08 '17 at 15:08

Ken

4

That's a dictionary comprehension – Chris_Rands Mar 08 '17 at 15:09
@Chris_Rands so the 'submit' functions are not actually called in this line? – Ken Mar 08 '17 at 15:18
You should follow the link and read about comprehensions. The answer to your question is yes, they are called. How about printing future_to_url at your interpreter? – Denziloe Mar 08 '17 at 15:22
Submit will be called for every element in URLS, the resulting value will the key in the dictionary – zinjaai Mar 08 '17 at 15:22

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