Python 列表的 “增删改查”方法

本文总结 Python 列表的 “增删改查”方法

具体如下

1.增

a = [1,2,3,4]
# list.reverse()
a.append(1)
print(a)
a.extend([0,1,2])
print(a)
a[len(a):]=[1]
print(a)
a[len(a):] = [1,2,3]
print(a)
a.insert(0,1.2)
print(a)
a.insert(len(a),9.2)
print(a)

#结果
# [1, 2, 3, 4, 1]
# [1, 2, 3, 4, 1, 0, 1, 2]
# [1, 2, 3, 4, 1, 0, 1, 2, 1]
# [1, 2, 3, 4, 1, 0, 1, 2, 1, 1, 2, 3]
# [1.2, 1, 2, 3, 4, 1, 0, 1, 2, 1, 1, 2, 3]
# [1.2, 1, 2, 3, 4, 1, 0, 1, 2, 1, 1, 2, 3, 9.2]

2.删

  

b = ["张三","李四","王五","赵六","A","B"]

b.remove("张三")
print(b)
b.pop(2)
print(b)
b.clear()
print(b)

#结果
# ['李四', '王五', '赵六', 'A', 'B']
# ['李四', '王五', 'A', 'B']
# []

3.改

c = ["a","b","c","d","e","f"]
#切片
c[0] = "A"
print(c)
c[1:3] = ["B","C"]
print(c)
num = [8,3,2,4,5]
#排序
num.sort()
print(num)
num.reverse()
print(num)
c.reverse()
print(c)

num= [8,3,2,4,5]
num.sort(reverse=True)
print(num)

#结果
# ['A', 'b', 'c', 'd', 'e', 'f']
# ['A', 'B', 'C', 'd', 'e', 'f']
# [2, 3, 4, 5, 8]
# [8, 5, 4, 3, 2]
# ['f', 'e', 'd', 'C', 'B', 'A']
# [8, 5, 4, 3, 2]

4.查

num = ["张三","李四","王五","赵六","A","B","A","C"]
print(num.count("A"))
print(num.index("张三"))

num[num.index("B")] = "b"
print(num)
print(num.index("A"))
print(num.index("A",-3,-1))

#浅拷贝
num_1 = num.copy()
print(num)
print(num_1)

num_2 = num[:]
print(num_2)


# 2
# 0
# ['张三', '李四', '王五', '赵六', 'A', 'b', 'A', 'C']
# 4
# 6
# ['张三', '李四', '王五', '赵六', 'A', 'b', 'A', 'C']
# ['张三', '李四', '王五', '赵六', 'A', 'b', 'A', 'C']
# ['张三', '李四', '王五', '赵六', 'A', 'b', 'A', 'C']