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alvas
alvas

Reputation: 122092

Why does len("".split(" ")) give 1? python

What is the pythonic explanation for len("".split(" ")) == 1 showing True?

Why does the "".split("") yield ['']

>>> len("".split(" "))
1
>>> "".split(" ")
['']

Upvotes: 8

Views: 5389

Answers (4)

fsw
fsw

Reputation: 3695

this might be relevant:

Why are empty strings returned in split() results?

split() is designed to be opposite of join() and:

" ".join([""]) == ""

Upvotes: 2

Hrishi
Hrishi

Reputation: 7138

[] has length zero. If a list contains anything in it, anything at all, it will have a length >=1 . In this case, [''] has one element in it: the empty string. So it gives one.

Upvotes: 4

beroe
beroe

Reputation: 12316

It is telling you the length of the list that is produced, not the length of the string.

Upvotes: 0

Martijn Pieters
Martijn Pieters

Reputation: 1122222

str.split(sep) returns at least one element. If sep was not found in the text, that one element is the original, unsplit text.

For an empty string, the sep delimiter will of course never be found, and is specifically called out in the documentation:

Splitting an empty string with a specified separator returns [''].

You probably are confused by the behaviour of the None delimiter option (the default):

If sep is not specified or is None, a different splitting algorithm is applied: runs of consecutive whitespace are regarded as a single separator, and the result will contain no empty strings at the start or end if the string has leading or trailing whitespace. Consequently, splitting an empty string or a string consisting of just whitespace with a None separator returns [].

(emphasis mine). That makes str.split(None) the exception, not the rule.

Upvotes: 22

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