Python列表的增删改查

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增：

append ：向列表最后增加元素,如果元素为列表，则以列表形式嵌套到父列表中

extend：通过extend可以将另一个集合中的元素逐一添加到列表中

insert：向列表特定位置增加元素

#！、usr/bin/python
names = ["zhang","wang",'li','zhao']
names.append("jia")
print(names)# display ['zhang', 'wang', 'li', 'zhao', 'jia']
names.insert(1,3)
print(names)# display ['zhang', 3, 'wang', 'li', 'zhao', 'jia']
names1 = ['a','b']
names2 = [1,2]
names1.append(names2)
print(names1)#['a', 'b', [1, 2]]
names1.extend(names2)
print(names1)#['a', 'b', [1, 2], 1, 2]

删：

del 根据下标进行删除

pop 删除最后一个元素

remove 根据元素的值进行删除

#!/usr/bin/python
names = ["zhang",'wang','li','zhao']
del names[2]
print(names)#display ['zhang', 'wang', 'zhao']
names = ["zhang",'wang','li','zhao']
names.pop()
print(names)#display  ['zhang', 'wang', 'li']
names = ["zhang",'wang','li','zhao']
names.remove("wang")
print(names)#display ['zhang', 'li', 'zhao']

改：

#!/usr/bin/python
names = ["zhang","wang","li","zhao"]
names[2] = "laoli"
print(names)#['zhang', 'wang', 'laoli', 'zhao']

查：

in

not in

index  请注意列表不能用find

count

#!/usr/bin/python
# in
names = ["zhang","wang","li","zhao"]
if "wang" in names:
        print("pass")
else:
        print("err")
# not in
if "wang" not in names:
        print("err")
else:
        print("pass")
# index
print(names.index("wang"))# 默认搜索整个列表
print(names.index("wang",0,3))#返回在指定切片中第一次出现的位置
# count
print(names.count("li"))#返回字符串在列表中出现的次数 

遍历方法实现查：

#!/usr/bin/python
flag = 0
names = ["zhang","wang","li","zhao"]
for name in names:
        if name == "zhang":
                flag = 1
                break
        else:
                flag = 0
if flag == 0:
        print("err")
else:
        print("pass")