Python3.7从无到有学习笔记

#Python3.7

1. 变量

>>> x=1
>>> y=2
>>> print(x+y)
3

2. 注释

#单行注释
'''多行注释'''

3. 布尔类型

>>> x=1
>>> y=2
>>> x<y
True
>>> x>y
False
#判断数值或者命令执行结果

3. 定义列表

>>> names = ["zhangsan","lisi","wangwu","zhaoliu","liubei"]
>>> names
["zhangsan","lisi","wangwu","zhaoliu","liubei"]

• 此处应用了列表中的隐藏语法：下标

names = ["zhangsan","lisi","wangwu","zhaoliu","liubei"]
names = ["0"			 ,"1"		,"2"		 ,"3"			 ,"4"			]
names = ["-5"			 ,"-4"	,"-3"		 ,"-2"		 ,"-1"			]

• 正数和倒数的区别

>>> names
['zhangsan', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']
>>> names[-4]
'wangwu'
>>> names[4]
'liubei'

• 插入

>>> names = ["zhangsan","lisi","wangwu","zhaoliu","liubei"]
>>> names[1]
'lisi'
>>> names.insert(1,"myc")
>>> names
['zhangsan', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei']

• 追加

>>> names.append("guanyu")
>>> names
['zhangsan', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']

• 删除

>>> names = ['zhangsan', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']
>>> names[1]
'myc'
>>> names[-6]
'myc'
>>> del names[-6]
#del names[1] 这么写也可以
>>> names
['zhangsan', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']

• 改

>>> names
['zhangsan', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']
>>> names [1] = "mayancheng"
>>> names
['zhangsan', 'mayancheng', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']

• 查，存在返回True，不存在返回False。和shell的0和1类似

>>> names
['zhangsan', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']
>>> "myc" in names
True
>>> "myc2" in names
False

• 查找并删除

>>> names
['zhangsan', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']
>>> names.index("myc")
1
>>> del names[names.index("myc")]
>>> names
['zhangsan', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']

• 查找并修改

>>> names
['zhangsan', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']
>>> names.index("myc")
1
>>> names[names.index("myc")] = "mayancheng"
>>> names
['zhangsan', 'mayancheng', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']

• 在指定位置前追加

>>> names
['zhangsan', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']
>>> names.insert(names.index("myc"),"mycgogogo")
>>> names
['zhangsan', 'mycgogogo', 'myc', 'lisi', 'wangwu', 'zhaoliu', 'liubei', 'guanyu']

• 读取用户指令

>>> names = input("请输入您的用户名：")
请输入您的用户名：vip
>>> names
'vip'
>>> print(names)
vip

• 格式化打印

%s	#字符串
input #接收到的所有数据都以字符串处理
%d	#整数
int		#接收到的数据以整数来处理
%f	#浮点数（小数）
float	#接收到的数据以浮点数来处理

name = input("姓名：")
age = int(input("年龄："))
height = float(input("身高："))
question = input("是否确认以上信息正确？")

msg = '''
=========Personal Info========
Name        : %s
Agg         : %d
Height      : %f
question    : %s
==============End=============
''' % (name,age,height,question)

print(msg)

if question == "y" or question == "Y":
    print("已记录")
else:
    print("请重新输入")