Python字典基础知识补充

1、添加键值对

#!/usr/bin/env python

i1 = {'k1':'cai' , 'k2':123}

print(i1)

i1['k3'] = 0

i1['k4'] = "rui"

print(i1)

=====================================

{'k1': 'cai', 'k2': 123}

{'k1': 'cai', 'k2': 123, 'k3': 0, 'k4': 'rui'}

2、修改字典中的值

#!/usr/bin/env python

i1 = {'k1':'cai' , 'k2':123}

print(i1)

i1['k1'] = 'rui'

print(i1)

================================

{'k1': 'cai', 'k2': 123}

{'k1': 'rui', 'k2': 123}

　　

3、删除键值对

i1 = {'k1':'cai' , 'k2':123}

print(i1)

del i1['k1']

print(i1)

=====================================

{'k1': 'cai', 'k2': 123}

{'k2': 123}

　

#!/usr/bin/env python

i1 = {'k1':'cai' , 'k2':123}

for key,value in i1.items():

    print(key,value)

=======================================

k1 cai

k2 123