如何使用enumerate迭代dict并解压缩索引，键和值以及迭代

问题描述

如何用enumerate迭代dict，以便在迭代时可以解开索引，键和值?

How to iterate dict with enumerate such that I could unpack the index, key and value at the time of iteration?

类似的东西:

for i, (k, v) in enumerate(mydict):
    # some stuff

我想遍历一本名为mydict的词典中的键和值，并对它们进行计数，所以我知道我何时读到最后一个.

I want to iterate through the keys and values in a dictionary called mydict and count them, so I know when I'm on the last one.

推荐答案

您应该使用 mydict.items() 与 enumerate 如:

Instead of using mydict, you should be using mydict.items() with enumerate as:

for i, (k, v) in enumerate(mydict.items()):
    # your stuff

示例:

mydict = {1: 'a', 2: 'b'}
for i, (k, v) in enumerate(mydict.items()):
    print("index: {}, key: {}, value: {}".format(i, k, v))

# which will print:
# -----------------
# index: 0, key: 1, value: a
# index: 1, key: 2, value: b

说明:

• enumerate返回一个迭代器对象，该对象包含格式为[(index, list_element), ...]
的元组.
• dict.items()返回迭代器对象(在Python 3.x中.在Python 2.7中返回list)，格式为:[(key, value), ...]
• 组合在一起时，enumerate(dict.items())将返回一个迭代器对象，该对象包含格式为[(index, (key, value)), ...]
的元组.

• enumerate returns an iterator object which contains tuples in the format: [(index, list_element), ...]
• dict.items() returns an iterator object (in Python 3.x. It returns list in Python 2.7) in the format: [(key, value), ...]
• On combining together, enumerate(dict.items()) will return an iterator object containing tuples in the format: [(index, (key, value)), ...]

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