Timeline for What do ** (double star/asterisk) and * (star/asterisk) mean in a function call?
Current License: CC BY-SA 4.0
18 events
| when toggle format | what | by | license | comment | |
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| Feb 13, 2023 at 20:21 | comment | added | Karl Knechtel |
@BenFarmer Yes; Python's dicts are iterable, and iterating over them yields the keys. So it is the same as if .keys() had been called on the dict first.
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| Feb 13, 2023 at 20:16 | history | edited | Karl Knechtel | CC BY-SA 4.0 |
simplify formatting, depersonalize language, update doc link, fix terminology (argument vs parameter), improve clarity, avoid using builtin name "sum"
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| Jun 1, 2022 at 3:12 | review | Suggested edits | |||
| Jun 1, 2022 at 9:00 | |||||
| Feb 17, 2019 at 4:06 | comment | added | H.C.Chen | The last example implies that * and ** are not only doing the unpacking but also packing! See this excellent page codingame.com/playgrounds/500/… | |
| Sep 15, 2017 at 7:47 | comment | added | Ben Farmer | What happens if you (accidentally perhaps :p) unpack a dictionary with only one * instead of two? It seems to do something, it seems like a tuple comes out, but it is not so obvious what it is. (edit: ok I think the answer is that it just unpacks the keys, the values are discarded) | |
| S Aug 28, 2014 at 4:18 | history | suggested | Zero | CC BY-SA 3.0 |
improved 'will execute as' semantics
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| Aug 28, 2014 at 3:58 | review | Suggested edits | |||
| S Aug 28, 2014 at 4:18 | |||||
| Jul 21, 2014 at 14:38 | review | Suggested edits | |||
| Jul 21, 2014 at 14:39 | |||||
| Mar 8, 2014 at 14:54 | comment | added | user445786 | To give some motivation coming from a C background, the * acts in an analogous way as the * operator in C, in that it 'dereferences' the variable. In python context, this means essentially 'removing the outer braces' of arrays or dictionaries. | |
| Nov 20, 2013 at 7:38 | comment | added | IceArdor | Here's the real benefit: you can write functions that wouldn't otherwise be possible if you need to have a variable number of arguments. For example, C's printf function, which has 1+n arguments, is tricky to write as an exercise for any beginning programmer. In Python, a beginner can write def printf(string_template, *args) and move on. | |
| Aug 7, 2013 at 15:05 | history | edited | Lasse V. Karlsen | CC BY-SA 3.0 |
fixed incorrect usage of "if neg"
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| Jul 8, 2013 at 22:24 | review | Suggested edits | |||
| Jul 8, 2013 at 22:45 | |||||
| Dec 11, 2010 at 15:18 | history | edited | Lasse V. Karlsen | CC BY-SA 2.5 |
fixed problem with "neg" option in response to email feedback
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| May 28, 2010 at 9:18 | vote | accept | psihodelia | ||
| May 27, 2010 at 14:29 | comment | added | Lasse V. Karlsen |
Sure, but then you would have to call it: s = sum((1, 2, 3, 4, 5)) or s = sum([1, 2, 3, 4, 5]), the *values option makes the call look like it takes a number of arguments, but they're packed up into a collection for the function code.
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| May 27, 2010 at 14:27 | comment | added | Martin Beckett | why would you need this, couldn't the function just iterate over the supplied list without it being expanded? | |
| May 27, 2010 at 14:22 | history | edited | Lasse V. Karlsen | CC BY-SA 2.5 |
added 583 characters in body; added 316 characters in body
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| May 27, 2010 at 14:15 | history | answered | Lasse V. Karlsen | CC BY-SA 2.5 |