python实现对列表的增删查修操作

#定义一个空列表

list_demo=[]

#1，向列表中插入元素

def  append_demo():    #第一种使用append，可以在列表末尾添加一个函数
    for i in range(2):
        list_demo.append(input())
    #输入one，two
    print(list_demo)
    #["one","two"]

#append_demo()

def extend_demo():      #第二种使用extend，可以在列表末尾添加多个元素
    list_one=[input() for i in range(2)]
    #输入测试列表["one","two","three"]
    list_demo.extend(list_one)
    print(list_demo)
    #["one","two","three"]

# extend_demo()

def insert_demo():       #第三种使用insert来完成,可以插入到列表中任一位置
    list_demo=["zero","one","two"]
    list_demo.insert(1,"text_demo")
    print(list_demo)
    #['zero', 'text_demo', 'one', 'two']

# insert_demo()



#2，删除列表元素

def remove_demo():        #remove删除函数可以删除任一指定的元素
    list_demo=["one","two","three"]
    list_demo.remove("one")
    print(list_demo)
    #['two', 'three']

#remove_demo()

def pop_demo():        #pop删除列表指定位的元素
    list_demo = ["one", "two", "three"]
    ele_one=list_demo.pop(1)  #列表删除并返回该元素
    print(ele_one)
    #two
    print(list_demo)
    #['one', 'three']

# pop_demo()

def del_dmeo():    #del可以直接删除列表中指定位置的元素
    list_demo=["zero","one", "two", "three"]
    del list_demo[1:3]
    print(list_demo)
    #['zero', 'three']

# del_dmeo()

#3,查找列表元素

def in_demo():    #通过in和not in 来判断一个元素是否在列表中
    list_demo=["zero","one", "two", "three"]
    if "one" in list_demo:
        print("yes")
        #yes
    if "good" not in list_demo:
        print("good")
        #good

# in_demo()

def count_demo(): #count可以返回元素在列表中出现的次数
    list_demo = ["zero", "one", "two", "three"]
    num=list_demo.count("three")
    print(num)
    #1

# count_demo()

def index_demo():    #index可以返回元素出现在列表中的位数
    list_demo = ["zero", "one", "two", "three"]
    num=list_demo.index("two")
    print(num)
    #2

# index_demo()

#4，对列表内的函数的修改

def change_demo():     #修改列表函数直接重新赋值即可
    list_demo = ["zero", "one", "two", "three"]
    list_demo[0]="good"
    print(list_demo)
    #['good', 'one', 'two', 'three']

change_demo()