python3-排序

排序

>>> z=[11,34,-12,9,8534,12,434]
>>> z.sort()
>>> z
[-12, 9, 11, 12, 34, 434, 8534]

sort() 函數(shù)用于對原列表進(jìn)行排序，如果指定參數(shù)，則使用比較函數(shù)指定的比較函數(shù)。

語法
sort()方法語法：

list.sort(cmp=None, key=None, reverse=False)
參數(shù)
參數(shù)
cmp -- 可選參數(shù), 如果指定了該參數(shù)會使用該參數(shù)的方法進(jìn)行排序。
key -- 主要是用來進(jìn)行比較的元素，只有一個(gè)參數(shù)，具體的函數(shù)的參數(shù)就是取自于可迭代對象中，指定可迭代對象中的一個(gè)元素來進(jìn)行排序。
reverse -- 排序規(guī)則，reverse = True 降序， reverse = False 升序（默認(rèn)）。

>>> y
[[3, 9], [1, 11], [5, 34], [2, 42], [4, 98]]
>>> y=[[1,11],[2,42],[3,9],[4,98],[5,34]]
>>> y.sort(key=lambda item:item[1])
>>> y
[[3, 9], [1, 11], [5, 34], [2, 42], [4, 98]]
>>>

>>> z=[{'id':'x1','length':13},{'id':'x2','length':201},{'id':'x3','length':98},{'id':'x4','length':9}]
>>> z
[{'id': 'x1', 'length': 13}, {'id': 'x2', 'length': 201}, {'id': 'x3', 'length': 98}, {'id': 'x4', 'length': 9}]
>>> z.sort(key=lambda item: item.get('length'))
>>> z
[{'id': 'x4', 'length': 9}, {'id': 'x1', 'length': 13}, {'id': 'x3', 'length': 98}, {'id': 'x2', 'length': 201}]
>>>

>>> z=[(1,"adsfafd"),(2,"qwer"),(3,"1234asf"),(4,"ew")]
>>> z
[(1, 'adsfafd'), (2, 'qwer'), (3, '1234asf'), (4, 'ew')]
>>> z.sort(key=lambda ele:ele[1])
>>> z
[(3, '1234asf'), (1, 'adsfafd'), (4, 'ew'), (2, 'qwer')]
>>> z.sort(key=lambda ele:len(ele[1]))
>>> z
[(4, 'ew'), (2, 'qwer'), (3, '1234asf'), (1, 'adsfafd')]
>>> z.sort(key=lambda ele:len(ele[1]),reverse=True)
>>> z
[(3, '1234asf'), (1, 'adsfafd'), (2, 'qwer'), (4, 'ew')]

多屬性排序

>>> z=[(1,"adsfafd"),(2,"qwer"),(3,"1234asf"),(4,"ew"),(2,"24")]
>>> z.sort(key=lambda ele:(len(ele[1]),ele[0]))
>>> z
[(2, '24'), (4, 'ew'), (2, 'qwer'), (1, 'adsfafd'), (3, '1234asf')]
>>>

#!/usr/bin/python

# 獲取列表的第二個(gè)元素
def takeSecond(elem):
    return elem[1]

# 列表
random = [(2, 2), (3, 4), (4, 1), (1, 3)]

# 指定第二個(gè)元素排序
random.sort(key=takeSecond)

# 輸出類別
print ('排序列表：', random)