python中列表和元组的操作(结尾格式化输出小福利)
一. 列表
1. 查
names = "YanFeixu WuYifan"
names_1 = ["YanFeixu"," WuYifan","Zhangsan"]
print(names)
print(names_1[0],names_1[2])
print(names_1[1:2]) # 切片
print(names_1[2]) # 切片
print(names_1[-1]) # 切片
print(names_1[-2:]) # 切片
2. 增
names_1 = ["YanFeixu"," WuYifan","Zhangsan"]
names_1.append("zhansgan") # 新增
names_1.insert(1,"Lisi") # 插入索引为1的前面
print(names_1)
3. 改
names_1 = ["YanFeixu"," WuYifan","Zhangsan"]
names_1[2] = "Zhuli"
print(names_1)
4. 删
names_1 = ["YanFeixu"," WuYifan","Zhangsan","Zhuli"]
names_1.remove("Zhangsan") # 删除的第一种方法
del names_1[1] # 删除的第二种方法
names_1.pop() # 默认删除最后一个
print(names_1)
5. 列表的方法
# 方法
names_1 = ["YanFeixu"," WuYifan","Zhangsan","Zhuli","Zhuli"]
print(names_1.index("Zhuli")) # 序号
print(names_1 [names_1.index("Zhuli")]) # 把Zhuli打印下来
print(names_1.count("Zhuli")) # 统计一下有几个Zhuli
names_1.reverse() # 把列表反转,也就是把序号颠倒
print(names_1)
names_1.sort() # 把列表按字母排序,先是符号,再是数字,再是字母
print(names_1)
names_2 = [1,2,3,4] # 扩展的方法,列表name_1和name_2合并了
names_1.extend(names_2)
print(names_1,"+",names_2)
import copy
# 方法
names_1 = ["YanFeixu"," WuYifan","Zhangsan",["Wangwu","Zhouliu"],"Zhuli","Zhuli"]
names_2 = names_1.copy() # 浅copy,只复制第一层,它变我不变(因为已经复制下来了),其余层它变我也变,外面是第一层**
print(names_1)
names_1[2] = "张三"
names_1[3][0] = "王五"
print(names_2)
names_1[2] = "张三"
names_3 = copy.deepcopy(names_1) # 深copy,就是克隆一份,具有自己单独的内存地址,两者完全不相干设,他变我不变
print(names_3)
二、元组
元组其实跟列表差不多,也是存一组数,只不是它一旦创建,便不能再修改,所以又叫只读列表
语法names = ("YanFeixu","jack","eric")
它只有2个方法,一个是count,一个是index。
小福利:
python中三引号的作用:
1 多行注释
print('Hello world!')
"""
这是一个
多行注释
注释,
###
"""
2 按照原格式输出文本(也就是格式化输出)
a = """ ###pandas features a number of
fnctions for reading 'tabular data' as
a DataFrame object. Such as , read_csv ...&&&;;;'''hello'''
"""
print(a)
输出结果:
3.格式化输出的案例:
案例(1)
name = input("name:")
age = input("age:")
job = input("job")
# 此处的三引号是格式化输出,不是注释!
info = '''------info of %s------
Name: %s
Age : %s
Job: %s
''' % (name,name,age,job)
print(info)
输出结果:
name:hzangsan
age:12
job:da
------info of hzangsan------
Name: hzangsan
Age : 12
Job: da
案例(2)
name_1 = input("name_1:")
age_1 = input("age_1:")
job_1 = input("job_1:")
info_1 = '''-----info of {name}------
Name: {name}
Age: {age}
Job: {job}
'''.format(name = name_1,
age = age_1,
job = job_1)
print(info_1)
输出结果:
name_1:zhansan
age_1:12
job_1:nishi
-----info of zhansan------
Name: zhansan
Age: 12
Job: nishi
此处有一个关于format的知识点:
username = input("username:")
print ("welcome {name} to our school".format(name = username ))
输出结果:
本人目前在学习python、前端、数据库和linux相关的内容,故打算写一些学习笔记,包括安装软件遇到的一些问题、编程语言的学习。 学习如逆水行舟,你在原地踏步的同时,别人一直在前进!