python字典中的元素个数 python元素为字典的列表

一、简单列表排序：

#正序
list = [1,5,3,4,2]
list.sort()
print(list)

#倒序
list = [1,5,3,4,2]
list.sort(reverse=True)
print(list)

二、列表元素是字典的排序：

#按一个关键词排序
list = [{'key':1},{'key':5},{'key':3},{'key':2},{'key':4}]
list.sort(key=lambda x:x['key'])
print(list)

#按二个关键词相加结果进行排序
list = [{'key1':1,'key2':1},{'key1':5,'key2':1},{'key1':3,'key2':6},{'key1':2,'key2':3},{'key1':4,'key2':9},]
list.sort(key=lambda x:x['key1']+x['key2'])
print(list)

三、字典排序

#简单字典排序
dict = {'a':1,'c':3,'b':2}
dict = sorted(dict.items(),key=lambda x:x[1])
print(dict)

#字典中含列表字典排序
dict = {'a':[{'key':2}],'c':[{'key':1}],'b':[{'key':3}]}
dict = sorted(dict.items(),key=lambda x:x[1][0]['key'])
print(dict)