python遍历字典的keys python如何遍历字典的键值

dict1 = {"a": "A", "b": "B"}

# 遍历字典所有key值
for k in dict1.keys():
    print(k)
# 遍历字典所有key值另一种写法
for k in dict1:
    print(k)
# 遍历字典中所有values值
for v in dict1.values():
    print(v)
# 遍历字典中所有values值另一种写法
for k in dict1:
    print(dict1[k])

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python 根据字典的键值进行排序
1、利用key排序

d = {'d1':2, 'd2':4, 'd4':1,'d3':3,}
for k in sorted(d):
    print(k,d[k])
'''
d1 2
d2 4
d3 3
d4 1
'''

2、利用value排序：getitem

d = {'d1':2, 'd2':4, 'd4':1,'d3':3,}
for k in sorted(d,key=d.__getitem__):
    print(k,d[k])
'''
d4 1
d1 2
d3 3
d2 4
'''

反序：reverse=True

d = {'d1':2, 'd2':4, 'd4':1,'d3':3,}
for k in sorted(d,key=d.__getitem__,reverse=True):
    print(k,d[k])
'''
d2 4
d3 3
d1 2
d4 1
'''

3、对dict_items进行排序

d = {'d1':2, 'd2':4, 'd4':1,'d3':3,}
res = sorted(d.items(),key=lambda d:d[1],reverse=True)
print(res)
'''
 [('d2', 4), ('d3', 3), ('d1', 2), ('d4', 1)]
'''