【python】字典超详解
注：最后有面试挑战，看看自己掌握了吗
文章目录
键值对dict—哈希表构成（无序）
不能直接修改键， 本质是哈希表，键不能重复！ 值可以是python支持的任何对象
增
法1
if '__main__' == __name__:
d={1:123,2:569}
d[3] = 123
print(d)法2
setdefault函数，默认为None
if '__main__' == __name__:
d={1:123,2:569}
d.setdefault(3,'129z')
print(d)查
法1
d={1:123,2:569}
d.setdefault(3,'129z')
print(d[2])法2
if '__main__' == __name__:
d = {1: 123, 2: 569}
d.setdefault('zzz', '129z')
print(d.get('zzz'))改
法1
法2-也可用来新增
if '__main__' == __name__:
d = {1: 123, 2: 569}
d.setdefault('zzz', '129z')
d.update({'zzz':'111'})
print(d.get('zzz'))删
法1
del函数
from Box_model import *
import math
import sys
if '__main__' == __name__:
d = {1: 123, 2: 569}
d.setdefault('zzz', '129z')
d.update({'zzz':'111'})
print(d.get('zzz'))
del(d[1])
print(d)法2
if '__main__' == __name__:
d = {1: 123, 2: 569}
p = d.pop(1)
print(p)法3
随机返回一个键值对元组，并且删除对应元素
if '__main__' == __name__:
d = {1: 123, 2: 569}
p = d.popitem()
print(p)if '__main__' == __name__:
d = {1: 123, 2: 569}
k,v = d.popitem()
print(v)遍历
遍历所有键值对
item()–以元组返回所有字典元素
if '__main__' == __name__:
d = {1: 123, 2: 569}
for item in d.items():
print(item)if '__main__' == __name__:
d = {1: 123, 2: 569}
print(d.items())//<class 'builtin_function_or_method'>遍历所有键
if '__main__' == __name__:
d = {1: 123, 2: 569}
for i in d:
print(i)if '__main__' == __name__:
d = {1: 123, 2: 569}
for i in d.keys():
print(i)遍历所有值
if '__main__' == __name__:
d = {1: 123, 2: 569}
for i in d.values():
print(i)if '__main__' == __name__:
d = {1: 123, 2: 569}
for i in d:
print(d[i])其他方法
in
if ‘item’ in dclear
copy
if '__main__' == __name__:
d = {1: 123, 2: 569}
d2 = d.copy()
print(id(d))
print(id(d2))
2757616058112
2757616058304if '__main__' == __name__:
d = {1: 123, 2: 569}
d2 = d
print(id(d))
print(id(d2))
2818139340544
2818139340544fromkeys-指定相关键 生成 空值字典
if '__main__' == __name__:
d = {}.fromkeys('1','zzz')
print(d)
{'1': 'zzz'}本文参与 腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。
原始发表：2023-02-25，如有侵权请联系 cloudcommunity@tencent.com 删除
评论
登录后参与评论
推荐阅读
目录