Python 内建函数 - len(s)

Manual

Return the length (the number of items) of an object. The argument may be a sequence (such as a string, bytes, tuple, list, or range) or a collection (such as a dictionary, set, or frozen set).

直译

返回对象s的长度（或项数）。该参数可以是序列（例如字符串、字节、元组、列表或区间）或集合（例如字典、集或冻结集）。

实例

>>> a = '优快云'
>>> len(a)
4

>>> b = bytes('优快云', 'utf-8')
>>> len(b)
4

>>> import os, sys
>>> c = (sys, os)
>>> len(c)
2

>>> d = ['H', 'e', 'l', 'l', 'o']
>>> len(d)
5

>>> e = set(d)
>>> len(e)
4

>>> f = frozenset(d)
>>> len(f)
4

>>> g = {'Friday': 0, 'Wednesday': 0, 'Monday': 0, 'Sunday': 0, 'Tuesday': 0, 'Saturday': 0, 'Thursday': 0}
>>> len(g)
7