Iterator

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iter(iterable)
next(iterator)

List

list(iterator) 创建一个新的列表，包含迭代器中的所有元素

Dictionary

values, keys, items can be iterated using iter() and next() functions

迭代的时候不要改变字典的结构（长度），否则会导致迭代出错

for r in range…

if use iterator in for statement, it will not be able to use again, because it will be exhausted after first iteration

built-in functions in Python

LAZY MODE:

map / filter / zip / reversed

map / filter

filter see data100 😋

zip

unpack the zip object into multiple variables(can be useful!)

why Iterator?