初识python

1、注释：

#注释单行
"""注释多行"""
'''注释多行'''
三个单引号或三个双引号还可以表示打印多行

2、变量：

#Author:Devin
name = "devin"
print("my name is", name ) #my name is devin
name2 = name
name = "tom"
print(name, name2) #tom devin

msg = """
tom
jack
lucy
"""
print(msg) #tom
           #jack
           #lucy

 3、格式化字符串示例：

#Author:Devin
name = input("name: ")
age = input("age: ")
job = input("job: ")
salary = input("salary: ")
info1 = """
--------info of %s------
name:%s
age:%s
job:%s
salary:%s
""" % (name, name, age, job, salary)
print(info1)
info2 = """
--------info of {_name}------
name:{_name}
age:{_age}
job:{_job}
salary:{_salary}
""".format(_name=name,
           _age=age,
           _job=job,
           _salary=salary)
print(info2)

 4、字符串与列表互相转换

#Author:Devin
name = "my name is devin"
print(name.split())
print(','.join(name.split()))

 5、集合常见的操作

#Author:Devin
list_1 = [1, 2, 3, 4, 5, 6]
list_1 = set(list_1)
print(list_1,type(list_1)) #{1, 2, 3, 4, 5, 6} <class 'set'>
list_2 = set([5, 6, 7, 8, 9])

#交集
print(list_1.intersection(list_2)) #{5, 6}
print(list_1 & list_2)

#并集
print(list_1.union(list_2)) #{1, 2, 3, 4, 5, 6, 7, 8, 9}
print(list_1 | list_2)

#子集
list_3 = set([2, 4])
print(list_3.issubset(list_1)) #True
print(list_3 <= list_1)

#父集
print(list_1.issuperset(list_3)) #True
print(list_1 >= list_3)

#差集：在list_1中而不再list_2中
print(list_1.difference(list_2))
print(list_1 - list_2) #{1, 2, 3, 4}

#对称差集：去除list_1和list_2交集的部分
print(list_1.symmetric_difference(list_2))
print(list_1 ^ list_2) #{1, 2, 3, 4, 7, 8, 9}

#往集合中添加一项
list_3.add(9999)
print(list_3) #{2, 4, 9999}

#往集合中添加多项
list_3.update(['tom', 'jim'])
print(list_3) #{2, 4, 9999, 'tom', 'jim'}

#删除集合中的一项
list_3.remove(9999)
print(list_3) #{2, 4, 'jim', 'tom'}

#查看长度
print(len(list_3)) #4

#查看jim是否在list_3中
print('jim' in list_3) #True

#这里的copy为浅copy
c = list_3.copy()
print(c)