python语法

type

用来检测数据类型

num = 1
print(type(num))

格式化占位符

name = 'fdas'
num = 1
print('wds=%s, dfd=%06d' % (name, num))

python语法插图

b = 2.325
print('fsda%.7f' % b)
print("wdw%%fwe%%" %())
wdw%fwe%
name = 'fdfd'
age = 324
print(f'名字{name},年龄{age}')
名字fdfd,年龄324

算术运算符

print(1+1)
print(6-5)
print(6*4)
print(6/3)

取整除

print(6//4)

1

幂次方

print(2**5)

32

输入函数

name = input("Enter your name: ")
print(name)

转义字符

print('fsdf\tfsdfsd')
print('fsdafd\nfdsaf\n')
print('fsdf\rfds')
fds
age = 10
if 0 <= age <= 5:
    print('1')
elif 10<= age <= 18:
    print('2')
else:
    print('3')
i=1
while i<100:
    print(i)
    i=i+1
str = 'fsdafsaf'
for i in str:
    print(i)
for i in range(1,5):  #左闭右开 1234
    print(i)
str = '你好'
str1 = str.encode('utf-8')
print(str1)
str2 = str1.decode('utf-8')
print(str2)
print("ads"+'das')

print('fsdaf\n'*3)
name = 'wang'
print('n' in name)
print('z' in name)
name = "fdsjflsd"
print(name[0])
str = 'fsdfasf' #左闭右开
print(str[0:5:2])
fda
print(str[3:5])
fa
print(str[-1:])
f
print(str[-1:-5:-1])
fsaf
print(str[:-1])
fsdfas

 

name = 'abcdefgabcdefg'
print(name.find('g'))
# 6
print(name.find('cd'))
# 2
print(name.find('d',6))
# 10
找不到-1
name = 'abcdefgabcdefg'
print(name.index('g'))
# 6
print(name.index('cd'))
# 2
print(name.index('d',6))
# 10
找不到就报错
name = 'qwerqwer'
print(name.count('q'))
2
print(name.count('A'))
0
print(name.count('q',3))
1
name = 'abcdefg'
print(name.capitalize())
# Abcdefg
print(name.startswith('a'))
# True
print(name.endswith('a'))
#False
print(name.lower())
# abcdefg
print(name.upper())
# ABCDEFG
#替换
name = '你好,你们好'
print(name.replace('你','他'))
# 他好,他们好
print(name.replace('你','他',1))
# 他好,你们好
name = 'a,bc,de,fg'
print(name.split(','))
# ['a', 'bc', 'de', 'fg']
print(name.split(',',1))
# ['a', 'bc,de,fg']
#列表
list=[1,2,'sfsd','3.2']
print(list)
# [1, 2, 'sfsd', '3.2']
print(list,type(list))
# [1, 2, 'sfsd', '3.2'] <class 'list'>
print(list[0])
# 1
print(list[0:3])
# [1, 2, 'sfsd']
for i in list:
    print(i)
# 1
# 2
# sfsd
# 3.2
list = ['one','two','three']
list.append('four')
print(list)
# ['one', 'two', 'three', 'four']
list.insert(0,'five')
print(list)
# ['five', 'one', 'two', 'three', 'four']
list.extend(['six','seven'])
print(list)
# ['five', 'one', 'two', 'three', 'four', 'six', 'seven']
list.extend('six')
print(list)
# ['five', 'one', 'two', 'three', 'four', 'six', 'seven', 's', 'i', 'x']
name = ['li','wang',1]
name[2] = 'shi'
print(name)
# ['li', 'wang', 'shi']

list = ['a','b','c']
print('a' in list)
# True
list = ['one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight']
del list[0]
print(list)
# ['two', 'three', 'four', 'five', 'six', 'seven', 'eight']
list.pop(0)
print(list)
# ['three', 'four', 'five', 'six', 'seven', 'eight']
list.remove('six')
print(list)
# ['three', 'four', 'five', 'seven', 'eight']
list = [1,2,3,5,6,8]
list.sort()
print(list)
# [1, 2, 3, 5, 6, 8]
list.reverse()
print(list)
# [8, 6, 5, 3, 2, 1]
list = []
for i in range(1,11):
    if i % 2 == 0:
        list.append(i)
print(list)
# [2, 4, 6, 8, 10]
[list.append(i) for i in range(1,11) if i % 2 == 0]
print(list)
# [2, 4, 6, 8, 10, 2, 4, 6, 8, 10]
list = [1,2,[8,52,5]]
print(list[1])
# 2
print(list[2][2])
# 5
元组
tup = (1,2,5,6)
print(type(tup))
# <class 'tuple'>
print(tup[0])
# 1
print(tup.index(5))
# 2
#字典
dic = {'name':'fsd', 'age':18}
print(dic['name'])
# fsd
print(type(dic))
# <class 'dict'>
dic = {'name':'fsd', 'age':18}
print(dic.get('name'))
# fsd
print(dic.get('number','没有'))
# 没有
dic['sex'] = 'male'
print(dic)
# {'name': 'fsd', 'age': 18, 'sex': 'male'}

del dic['name']
print(dic)
# {'age': 18, 'sex': 'male'}
dic.pop('age')
print(dic)
# {'sex': 'male'}
dic.clear()
print(dic)
# {}
dic = {'name':'fsd', 'age':18, 'sex':'male'}

print(len(dic))
# 3
print(dic.keys())
# dict_keys(['name', 'age', 'sex'])

for i in dic.keys():
    print(i)
# name
# age
# sex

for i in dic.values():
    print(i)
# fsd
# 18
# male

for i in dic.items():
    print(i)
# ('name', 'fsd')
# ('age', 18)
# ('sex', 'male')
#集合,无序性
set1 =  {'a','b','c','d','e','f','g','h'}
print(set1)
{'d', 'g', 'e', 'a', 'c', 'f', 'b', 'h'}
set2 = {1,2,3,4,5}
print("原来的",set2)
set2.add(6)
print(set2)

set2.update({6,7})
print(set2)
# {1, 2, 3, 4, 5, 6, 7}
set2.update("89")
print(set2)
# {1, 2, 3, 4, 5, 6, 7, '9', '8'}
set2.remove(6)
print(set2)
# {1, 2, 3, 4, 5, 7, '9', '8'}
set2.pop()
print(set2)
# {2, 3, 4, 5, 7, '9', '8'}
set2.discard(4)
print(set2)
# {2, 3, 5, 7, '8', '9'}
set1 = {1,3,6,8}
set2 = {1,5,8}
print(set1&set2)
# {8, 1}
print(set1|set2)
# {1, 3, 5, 6, 8}
print(eval('1+1'))
# 2
import copy
list = [1,2,3]
list2 = list
print(list)
print(list2)
list2.append(4)
print(list)
# [1, 2, 3, 4]
print(list2)
# [1, 2, 3, 4]

list3 = copy.copy(list)
print(list3)
list.append(5)
print(list)
# [1, 2, 3, 4, 5]
print(list3)
# [1, 2, 3, 4]

#深拷贝数据变化只影响自己
list4 = [1,2,[5,6]]
list5 = copy.deepcopy(list4)
print(list5)
list4.append(7)
print(list5)
# [1, 2, [5, 6]]
print(list4)
# [1, 2, [5, 6], 7]
def login():
    print("denglu")
login()
def buy():
    return 0
print(buy())

def add(a,b):
    return a+b
print(add(1,2))
def func(a=1):
    print(a)
func()
func(5)
# 5

def func2(*args):
    print(args)
    print(type(args))
func2(1)
# <class 'tuple'>

def func3(**kwargs):
    print(kwargs)
    print(type(kwargs))
func3()
func3(name = 'ff',age = 10)
# {'name': 'ff', 'age': 10}
# <class 'dict'>
add = lambda a,b: a+b
print(add(1,2))
add = lambda a,b: a+b
print(add(1,2))