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：