python实现增删改查操作

# 增加操作
# append在列表的尾部加入指定的元素
name_list = ["小明","小强","小红"]
name_list.append("小花")
print(name_list)

# extend将指定序列的元素依次追加到列表的尾部(合并),不会去重复内容
# name_list2 = ["小猪","小猫",'小明']
# name_list.extend(name_list2)
# print(name_list)
#
# # " + "加法 等价于 extend 方法
# name_list3=name_list+name_list2
# print(name_list3)
#
# # insert将指定的元素插入到对应的索引位上，注意负索引倒序插入，超过索引就会在末尾插入
# name_list.insert(0,"小尹")
# name_list.insert(-3,"小黄")
# print(name_list)

# 删除操作
# pop弹出，返回并删除指定索引位上的数据，默认删除索引为-1的数据(从右向左删除)
# name = name_list.pop(1)
# print(name)
# #指定索引删除
# print(name_list)
# del删除整个列表或列表的数据，del是python内置功能，不是列表独有的
# del name_list[0]
# print(name_list)
# remove删除一个指定的元素
# name_list.remove("小强")
# print(name_list)
# clear 清空列表
# name_list.clear()
# print(name_list)


# 修改操作
# name_list[0]="小白"
# print(name_list)

# 查找操作
# 使用索引
name_list=["tom","jerry","array","tom"]
# name=name_list[2]
# print(name)
# index查找，从左往右返回查找到的第一个指定元素的索引，如果没有找到，报错
# index=name_list.index("jerry")
# print(index)
# count计数，返回要计数的元素在列表当中的个数
num=name_list.count("tom")
print(num)

# 默认排序
# lst1=["abd","ABD","aBe"]
# lst1.sort()
# print(lst1)

# 指定排序规则
# lst1=["abd","ABD","aBc"]
# lst1.sort(key=str.lower)
# print(lst1)
# # reverse()翻转
# lst1=["abc","ABD","aBe"]
# lst1.reverse()
# print(lst1) # ["aBe","ABD","abc"]
# lst1=["abc","ABD","aBe"]
# print(lst1)
# lst2=sorted(lst1)
# print(lst2) # ["ABD","aBe","abc"]
# lst3=sorted(lst1,key=str.lower)
# print(lst3) # ["abc","ABD","aBe"]
# lst4=sorted(lst1,reverse=True)
# print(lst4) # ["abc","aBe","ABD"]