本文主要介绍Python入门到精通-了解Python数据类型，通过具体的内容向大家展现，希望对大家Python程序开发的学习有所帮助。

字符串类型

字符串是通过一个或多个元素组成的序列。

字符串一般使用的 单引号，双引号，三单引号，三双引号标识。

转义符

r 禁用转义符号

\n 换行

\b 退格

\r 回车

\t 制表符

\? 一个问号

练习代码

str1 = "Hello World !"

str2 = '''   ssss

sssssss'''

print(str1,str2)

str3 = "你好 中国"

print(str3)

#切片

str4 = "hello I am zhangsan!"

print(str4[8])

print(str4[:5])  #终止位置不包含第五个元素，起始位置0可以省略。

print(str4[5:])    #起始位置包含第五个元素，起始位置0可以省略。

print(str4[-10:-1])

#拼接

str5 = "Hello"

str6 = "World !"

str7 = "123"

print(str5 + ' ' +  str6 + str7) # 字符拼接不能是int类型

#字符串格式化

name = "zzzz"

age = 123

newage = str(age)     # str()用于转换成字符串

print(type(newage))

print("my name is %s, my age is %d" %(name,age))  # %s字符串  %d 数值

msg = "my name is {0}, my age is {1}".format(name,age)

print(msg)

# 转义字符

new1 = r"abc \n cba"

print(new1)

内置函数

capitalize()

count()

decode()

encode()

endswith()

startswith()

find()

index()

isalpha()

lstrip()/rstrip()/strip()

replace()

upper()

split()

reponse = "  abcd123  45abcd  "

print(reponse.capitalize())   #将字符串开头字母大写

print(reponse.count('b',2,len(reponse)))    #统计元素出现的次数,参数：元素，起始位置，结束位置

print(reponse.encode(encoding="UTF-8"))   #以某种编码加密字符串

newreponse = reponse.encode(encoding="UTF-8")

print(newreponse.decode(encoding="UTF-8"))   #以某种编码解码字符串

print(reponse.startswith("b"))  # 判断字符串以某个元素开头，True、False

print(reponse.endswith("c"))    # 判断字符串以某个元素结尾，True、False

print(reponse.find("ac"))   # 根据某个元素进行查找，0、-1

print(reponse.index('b'))  #返回元素的索引，-1

print(reponse.isalpha())   #判断字符串中元素是否都是字母，True、False

print(reponse.lstrip())  #去掉字符串左侧空格

print(reponse.rstrip())  #去掉字符串右侧空格

print(reponse.strip())   #去掉字符串前后空格

print(reponse.replace("  ",""))  # 替换元素

print(reponse.upper())  #将字符串所有的字符转换成大写

print(reponse.split("  "))   #根据元素分割，列表

数字类型

分类

整型

布尔型

浮点型

复数类型

运算符

+ - * / % > = < >= <= ==

练习代码

age = 45    # 正整数

memory = -100   #负整数

a = 0x768A   #十六进制表示的正整数

print("my age is : %d, my memory is : %d" % (age,memory))

print(a)

a = True

b = False

print(int(a),int(b))

c = 1.2

d = 2.4

print(c,type(d))

a = 123

b = 456

print("a + b = " + str(a+b) )

print("a - b = " + str(a-b))

print("a * b = " + str(a*b))

print("a / b = " + str(a /b) )

print("a > b " + str(a > b))

print("a < b " + str(a<b))

列表类型 list

内置函数

append()

count()

extend()

index()

insert()

pop()

remove()

reverse()

练习代码

##定义

a = []

print(type(a))

numlist = [1,2,3,4,5,6]

strlist = ["a","b","c","d"]

print(numlist,strlist)

##获取list元素

print(numlist[3],strlist[2])

print(numlist[:5])

print(len(numlist))

## 应用

ipAddress = [r"192.158.0.1",r"192.168.0.2"]

print(ipAddress)

## 遍历

for ip in ipAddress:

    print(ip)

#内置函数

testHosts = ["aa","bb","cc","dd"]

t1 = ["dd","cc"]

testHosts.append("EE")   #末尾追加

print(testHosts.count('bb'))   # 计算元素出现的次数

print(testHosts.extend(t1))    # 扩展列表、合并列表

print(testHosts.index("EE"))   # 获取列表中元素的索引

testHosts.insert(5,"DD")  #列表中插入元素 ，参数：索引，元素

print(testHosts)

print(testHosts.pop(2))   #根据索引删除元素，并返回被删元素

print(testHosts)

testHosts.remove("EE")  ##删除元素

print(testHosts)

testHosts.reverse()  #反向列表

print(testHosts)

元组类型

元组中元素是不可进行修改的

#定义

a = ()

print(type(a))

a = (1,2,3,4,5)

b = ("aa","bb","cc")

print(a,b)

#应用

test = ("java","tomcat","springboot")

print(test[1])

print(test[:2])

test1 = ([1,2,3],"aa")

print(test1)

test1[0].append(123)

print(test1)

字典类型

key/value

内置函数

clear()

copy()

get()

items()

keys()

update()

pop()

values()

练习代码

#定义

a = {}

print(type(a))

myinfo = {"name":"zhangsan","age":45}

print(myinfo)

print(myinfo['name'])

myinfo["job"] = "devops1"    #增加、修改元素

print(myinfo)

#内置函数

myinfo = {"name":"zhangsan","age":45}

#print(myinfo.clear())   #清空字典

print(myinfo)

data1 = myinfo.copy()   #复制一个独立的副本

print(data1)

data1["name"] = "lisi"

print(data1)

print(myinfo)

print(myinfo.get("name"))  #获取key 的值

print(myinfo.items())  #格式化将key和value组合成元组并存放到列表中

print(type(myinfo.items()))

print(myinfo.keys())   #获取所有的key

print(myinfo.values())  #获取所有的value

print(myinfo.pop("name"))  #通过key删除键值对

print(myinfo)

实战1- python格式化输出

## %

name = "zhangsan"

age = 45

print("my name is : %s , my age is %s" % (name,str(age)))

## format

name = "lisi"

age = 34

print("my name is {0}, my age is {1}".format(name,age))

## title

info = """

name = {0}

age = {1}

high = {2}

jobs = {3}

address = {4}

"""

print("---------------------")

print(info.format("zhangsan",24,178,"PythonDeveloper","Beijing"))

print("---------------------")

实战2- 列表增删改查

## append

## remove  pop

students = ["zhangsan","lisi","wangwu"]

## 添加同学

newStudent = "aa"

students.append(newStudent)

print("class students is : %s " %(students,))

## 合并班级

twoStudents = ["cc","dd","ee"]

students.extend(twoStudents)

print("class students is : %s " %(students,))

## 换班

moveStudent = "wangwu"

students.remove(moveStudent)

print("class students is : %s " %(students,))

## 更新

studentName = "zhangsanfeng"

stuindex = students.index("zhangsan")

students[stuindex] = studentName

print("class students is : %s " %(students,))

实战3- 将json数据转换成字典

import json

## dict -> json

myinfo = {"name":"zhangsan","age":100}

jsonInfo = json.dumps(myinfo)

print(type(jsonInfo))

## json -> dict

dictInfo = json.loads(jsonInfo)

print(type(dictInfo))

print(dictInfo['age'])

##

a = '{"name":"zhangsan"}'

print(json.loads(a))