说明 {#说明}

pairwise(iterable)是itertools下的一个方法
该方法是会返回传入列表所有相邻元素，如果传入的数据少于两个，会返回空

官方文档 {#官方文档}

Return successive overlapping pairs taken from the input iterable.

The number of 2-tuples in the output iterator will be one fewer than the number of inputs. It will be empty if the input iterable has fewer than two values.

Roughly equivalent to:

def pairwise(iterable):
    # pairwise('ABCDEFG') --> AB BC CD DE EF FG
    a, b = tee(iterable)
    next(b, None)
    return zip(a, b)

源码 {#源码}

在itertools.py文件中

class pairwise(object):
    """
    Return an iterator of overlapping pairs taken from the input iterator.

        s -> (s0,s1), (s1,s2), (s2, s3), ...
    """
    def __getattribute__(self, *args, **kwargs): # real signature unknown
        """ Return getattr(self, name). """
        pass

    def __init__(self, *args, **kwargs): # real signature unknown
        pass

    def __iter__(self, *args, **kwargs): # real signature unknown
        """ Implement iter(self). """
        pass

    @staticmethod # known case of __new__
    def __new__(*args, **kwargs): # real signature unknown
        """ Create and return a new object.  See help(type) for accurate signature. """
        pass

    def __next__(self, *args, **kwargs): # real signature unknown
        """ Implement next(self). """
        pass

参考代码 {#参考代码}

代码：

#!/usr/bin/env python3
# @Time : 2022/9/5 20:23
# @Author : 轩辕龙儿
# @File : pyPairwise.py 
# @Software: PyCharm
from itertools import pairwise
`if `name` == "`main`":
arrs = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
print("传入数据：0, 1, 2, 3, 4, 5, 6, 7, 8, 9")
for arr in pairwise(arrs):
print(str(arr[0]) + "," + str(arr[1]))
print("------------------------------------")
print("传入数据：1")
for arr in pairwise([1]):
print(str(arr[0]) + "," + str(arr[1]))
`

控制台输出：

"D:\Program Files\Python310\python.exe" D:/project/leet-code-python/study/pyPairwise.py 
传入数据：0, 1, 2, 3, 4, 5, 6, 7, 8, 9
0,1
1,2
2,3
3,4
4,5
5,6
6,7
7,8
8,9
------------------------------------
传入数据：1
`Process finished with exit code 0
`