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