Python sorted对list和dict排序

sorted语法

sorted(iterable, key=none, reverse=false)

参数说明：

 - iterable -- 可迭代对象。
 - key --主要是用来进行比较的元素，只有一个参数，具体的函数的参数就是取自于可迭代对象中，指定可迭代对象中的一个元素来进行排序。
 - reverse -- 排序规则，reverse = true 降序 ， reverse = false 升序（默认）。

返回：
 - 一个新list对象 

sorted对字典dict排序

①按键key排序

from operator import itemgetter
dict = {3: 'b', 1: 'a', 2: 'c'}

# 按key升序  .items()取得3个(key,value)
# lambda x: x[0]取(key,value)的key  即(3,1,2)
d1 = sorted(dict.items(), key=lambda x: x[0], reverse=false) # <class 'list'>

# 按key降序  itemgetter类似lambda
d2 = sorted(dict.items(), key=itemgetter(0), reverse=true) # <class 'list'>

# 输出
print(d1, type(d1)) # [(1, 'a'), (2, 'c'), (3, 'b')] <class 'list'>
print(d2, type(d2)) # [(3, 'b'), (2, 'c'), (1, 'a')] <class 'list'>

[(1, ‘a'), (2, ‘c'), (3, ‘b')] <class ‘list'>
[(3, ‘b'), (2, ‘c'), (1, ‘a')] <class ‘list'>

②按值value排序

from operator import itemgetter
dict = {3: 'b', 1: 'a', 2: 'c'}

# 按value升序  .items()取得3个(key,value)
# lambda x: x[1]取(key,value)的value  即('b','a','c')
d3 = sorted(dict.items(), key=lambda x: x[1], reverse=false) # <class 'list'>

# 按value降序  itemgetter类似lambda
d4 = sorted(dict.items(), key=itemgetter(1), reverse=true) # <class 'list'>

print(d3, type(d3)) # [(1, 'a'), (3, 'b'), (2, 'c')] <class 'list'>
print(d4, type(d4)) # [(2, 'c'), (3, 'b'), (1, 'a')] <class 'list'>

[(1, ‘a'), (3, ‘b'), (2, ‘c')] <class ‘list'>
[(2, ‘c'), (3, ‘b'), (1, ‘a')] <class ‘list'>

sorted排序list

①按一种规则排序list

from operator import itemgetter
data = [('c', 3, 'apple'), ('d', 1, 'cat'), ('a', 2, 'banana')]
# 根据字母升序
print(sorted(data, key=lambda x: x[0], reverse=false)) # <class 'list'>
# 根据数字升序
print(sorted(data, key=lambda x: x[1], reverse=false)) # <class 'list'>
# 根据单词升序
print(sorted(data, key=lambda x: x[2], reverse=false)) # <class 'list'>

[('a', 2, 'banana'), ('c', 3, 'apple'), ('d', 1, 'cat')]
[('d', 1, 'cat'), ('a', 2, 'banana'), ('c', 3, 'apple')]
[('c', 3, 'apple'), ('a', 2, 'banana'), ('d', 1, 'cat')]

②按多种规则排序list

# 先按照成绩降序排序，相同成绩的按照名字升序排序：
d1 = [{'name':'alice', 'score':38}, {'name':'bob', 'score':18}, {'name':'darl', 'score':28}, {'name':'christ', 'score':28}]
l = sorted(d1, key=lambda x:(-x['score'], x['name']))
print(l)

[{'name': 'alice', 'score': 38}, {'name': 'christ', 'score': 28}, {'name': 'darl', 'score': 28}, {'name': 'bob', 'score': 18}]

sorted排序list和dict的混合

 先看看我们排序的有哪些类型的数据结构

#### 二维list排序
l1 = [['bob', 95.00, 'a'], ['alan', 86.0, 'c'], ['mandy', 82.5, 'a'], ['rob', 86, 'e']]

#### list中混合字典
l2 = [{'name':'alice', 'score':38}, {'name':'bob', 'score':18}, {'name':'darl', 'score':28}, {'name':'christ', 'score':28}]

#### 字典中混合list
d1 = {'li': ['m', 7], 'zhang': ['e', 2], 'wang': ['p', 3], 'du': ['c', 2], 'ma': ['c', 9], 'zhe': ['h', 7]}

#### 对字典中的多维list进行排序
d2 = {
  'apple': [['44', 88], ['11', 33], ['22', 88]],
  'banana': [['55', 43], ['11', 68], ['44', 22]],
  'orange':[['22', 22], ['55', 41], ['44', 42], ['33', 22]]
}

二维list排序

from operator import itemgetter
l1 = [['bob', 95.00, 'a'], ['alan', 86.0, 'c'], ['mandy', 82.5, 'a'], ['rob', 86, 'e']]
# 按先按成绩号升序，再按成绩数值升序
print(sorted(l1, key=itemgetter(2, 1), reverse=false))
# 按先按成绩号升序，再按成绩数值降序序
print(sorted(l1, key=lambda x:(x[2], -x[1]), reverse=false))

[[‘mandy', 82.5, ‘a'], [‘bob', 95.0, ‘a'], [‘alan', 86.0, ‘c'], [‘rob', 86, ‘e']]
[[‘bob', 95.0, ‘a'], [‘mandy', 82.5, ‘a'], [‘alan', 86.0, ‘c'], [‘rob', 86, ‘e']]

2. list中混合字典

from operator import itemgetter
# 先按照成绩降序排序，相同成绩的按照名字升序排序：
l2 = [{'name':'alice', 'score':38}, {'name':'bob', 'score':18}, {'name':'darl', 'score':28}, {'name':'christ', 'score':28}]
print(sorted(l2, key=lambda x:(-x['score'], x['name'])))
print(sorted(l2, key=itemgetter('score', 'name')))

[{‘name': ‘alice', ‘score': 38}, {‘name': ‘christ', ‘score': 28}, {‘name': ‘darl', ‘score': 28}, {‘name': ‘bob', ‘score': 18}]
[{‘name': ‘bob', ‘score': 18}, {‘name': ‘christ', ‘score': 28}, {‘name': ‘darl', ‘score': 28}, {‘name': ‘alice', ‘score': 38}]

3. 字典中混合list

d1 = {'li': ['m', 7], 'zhang': ['e', 2], 'wang': ['p', 3], 'du': ['c', 2], 'ma': ['c', 9], 'zhe': ['h', 7]}
# sort返回的是list，如果需要转为dict，再sorted前面套一个dict()就可以了
print(sorted(d1.items(), key=lambda x:(x[1][1], -ord(x[1][0]) ))) # 对字符比较需要ord。如果是'123'字符串数字可以使用int。
# print(sorted(d1.items(), key=lambda x:(x[1][1], -ord(x[1][0]) )))

[(‘zhang', [‘e', 2]), (‘du', [‘c', 2]), (‘wang', [‘p', 3]), (‘li', [‘m', 7]), (‘zhe', [‘h', 7]), (‘ma', [‘c', 9])]

4. 对字典中的多维list进行排序

d2 = {
  'apple': [['44', 88], ['11', 33], ['22', 88]],
  'banana': [['55', 43], ['11', 68], ['44', 22]],
  'orange':[['22', 22], ['55', 41], ['44', 42], ['33', 22]]
}
for key, value in d2.items():
  d2[key] = sorted(value, key=lambda x:(x[1], -int(x[0]))) # 按list第二列升序，相同则按第一列降序，参考二维list排序
print(d2)

{‘apple': [[‘11', 33], [‘44', 88], [‘22', 88]], ‘banana': [[‘44', 22], [‘55', 43], [‘11', 68]], ‘orange': [[‘33', 22], [‘22', 22], [‘52', 41], [‘44', 42]]}

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