Python基础学习二

字典
dic = {
"省":{
"市": ['县']
}
}
dic.keys()
dic["省"].keys()
dic["省"]["市"]
返回的都是列表

列组
索引 index
切片 [:]
追加 append
删除 del remove pop
长度 len
循环 for while
break(循环不在进行);continue(下一次循环);pass(站位);return(终止);exit(退出)
包含 in __contains__

基本操作：
元组元素不可修改
(11,22,33,44)
(11,22,{'k1':'v1'})
元组元素的元素可以修改

#!/usr/bin/python
# -*- coding: utf8 -*-

t1 = (1,2,{'k1':'v1'})

#del t1[0]
#t1[2] = 123

t1[2]['k1'] = 2
print(t1)

(1, 2, {'k1': 2})

字典（键值对）
索引 keys
新增
删除 del d[key]
键、值、键值对
keys values items
for k in dic.keys
for v in dic.values
for k,v in dic.items
循环
长度

1.py __name__ 1
2.py __name__ 2
lib/3.py __name__ lib.3
index.py __name__ = '__main__'

python index.py

li = [11,22,33]
li = list((11,22,33))或者
li = list([11,22,33])
ret = li.pop()删除最后一个并把最后一个元素赋值给ret
ret = li.pop(0)删除下标为0的元素，并把这个元素赋值给ret

s = "abc"
s = str('abc')

print(type(s)) ----> str
print(dir(s)) ----> 成员

result = s.center(7,'*')
print(result) ---> **abc**

find 和index都可以找字符或者字符串 找到之后返回下标 find找不到就返回-1 index找不到报错

name = "you {0} as {1}"
result = name.format('hh','ww')
print(result) --->you hh as ww

li = ['s','b','y','u']
result = "_".join(li)
print(result) ---> s_b_y_u

with open('text.txt') as f:
f.wirte()
不用加f.close()会自己关闭文件

li = [11,11,2,22]
print(li)
li.remove(11)
print(li) --->[11,2,22] remove只删除第一个

# -*- coding: utf-8 -*-
li = [1,2,3,4,5,6,7,8,9]
print(li)

li.append(10)
print(li)

li.extend([11,12])
print(li)

li.reverse()
print(li)

ret = li.pop(6)
print(ret)
print(li)

# -*- coding: utf-8 -*-
li = [1,2,3,4,5,6,7,8,9]

tu = (1,2,3,4,5,6,7,8,9)
print("li值=%s" %(li))
print("li类型=%s" %(type(li)))
print(tu)
print("tu类型=%s" %(type(tu)))

print(list(tu))
print(tuple(li))

字典
# -*- coding: utf-8 -*-
dic = dict(k1='v1',k2='v2')
print(dic) #{'k2': 'v2', 'k1': 'v1'}
new_dict = dic.fromkeys(['k1','k2','k3'],'v1')
print(new_dict) #{'k3': 'v1', 'k2': 'v1', 'k1': 'v1'}

dic = {'k1':'v1','k2':'v2'}
print(dic['k1'])
print(dic['k2'])
print(dic.get('k1'))
print(dic.get('k2'))
print(dic.get('k3'))
print(dic.get('k3','meiyou'))
v1
v2
v1
v2
None
meiyou

dic = {'k1':'v1','k2':'v2'}
print(dic.keys())
print(dic.values())
print(dic.items())
['k2', 'k1']
['v2', 'v1']
[('k2', 'v2'), ('k1', 'v1')]

字典是无序的所以dic.pop()的时候要指定关键字
如dic.pop('k1')

dic.popitem()随便删除一个

dic['k3'] = 123
dic.setdefault('k4',456) #不指定值得话默认为None
print(dic)
{'k3': 123, 'k2': 'v2', 'k1': 'v1', 'k4': 456}

dic = {'k1':'v1','k2':'v2'}
print(dic)
dic.update({'k3':123}) #更新字典，相当于列表的extend()
print(dic)

# -*- coding: utf-8 -*-

all_list = [11,22,33,44,55,66,77,88,99]

dic = {}

list_one = []

list_two = []

for i in all_list:

if i > 55:

list_one.append(i)

else:

list_two.append(i)

dic['k1'] = list_one

dic['k2'] = list_two

print(dic)
{'k2': [11, 22, 33, 44, 55], 'k1': [66, 77, 88, 99]}

# -*- coding: utf-8 -*-
all_list = [11,22,33,44,55,66,77,88,99]

dic = {}
for i in all_list:

if i > 55:

if 'k1' in dic.keys():

dic['k1'].append(i)

else:

dic['k1'] = [i,]

else:

if 'k2' in dic.keys():

dic['k2'].append(i)

else:

dic['k2'] = [i,]
print(dic)
{'k2': [11, 22, 33, 44, 55], 'k1': [66, 77, 88, 99]}