What does str_var[:] mean in python?

Asked Oct 10 '17 at 13:49

Active Oct 10 '17 at 14:03

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I am parsing text for NLP. And I faced unfamiliar grammer below url.

text[:] https://github.com/facebookresearch/ParlAI/blob/master/parlai/core/dict.py#L39

I assume text is a natural sentence like text = 'what does Duane Boutte appear in?'. I know : with index number means array access like text[:3] -> 'wha'. But I do not know without index number. And I also know : is used for access to multi dimensional array like data[:][:3].

Could you image above link's text[:]? This function split sentence to tokens.

Update

I found it is a copy operation. See Martijn Pieters and Jean-François Fabre comments

edited Oct 10 '17 at 14:03

asked Oct 10 '17 at 13:49

jef

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It creates a copy from start to end; it is sometimes called the *identity slice*. – Martijn Pieters Oct 10 '17 at 13:50
Thanks! Is it same as `copy.deepcopy(text)`? – jef Oct 10 '17 at 13:51
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rather like `copy.copy(text)` – Jean-François Fabre Oct 10 '17 at 13:52
Nice. I don't know that. If it's' possible, could you post your comment as an answer? I will mark it as an answer – jef Oct 10 '17 at 13:56
errr, no since it's a duplicate. but thanks. – Jean-François Fabre Oct 10 '17 at 13:58
note that identity slice on a string does nothing useful since strings are immutable: https://stackoverflow.com/questions/5722006/does-python-do-slice-by-reference-on-strings – Jean-François Fabre Oct 10 '17 at 13:58

What does str_var[:] mean in python?

Update

0 Answers0