【Python】数组的增删改查

1. 增加元素

# 普通数组

a = [1, 2, 3]

a.append(4)

print(a) # output: [1, 2, 3, 4]

# Numpy 数组

a2 = np.array([1, 2, 3])

aa2 = np.append(a2, 5)

print(aa2) # output: [1 2 3 5]

2. 插入元素

# 普通数组

a = [1, 2, 3]

a.insert(1, 33)

print(a) # output: [1, 33, 2, 3]

# Numpy数组

a2 = np.array([1,2,3])

a3 = np.insert(a2, 1, 33)

print(a3) # output: [1 33 2 3]

3. 删除元素

# 普通数组

a = [1, 2, 3]

a.remove(3) # 删除值是3的第一个元素

print(a) # output: [1, 2]

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a = [1, 2, 3]

a.pop(1) # 删除索引是1的元素

print(a) # output: [1, 3]

print(a.pop(1)) # output: 3

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a = [1, 2, 3, 4]

del a[0:2]

print(a) # output: [3, 4]

# Numpy数组

a2 = np.array([1,2,3])

a3 = np.delete(a2, 0) # 删除索引的值

print(a3) # output: [2 3]

4. 修改元素（普通数组和Numpy数组，修改方式一致）

# 普通数组，修改元素

a = [1, 2, 3, 4]

a[0] = 5

print(a) # output [5, 2, 3, 4]

# Numpy数组，修改元素

a2 = np.array([1,2,3,4])

a2[0] = 5

print(a2) # output [5 2 3 4]

5. 查找元素

# 普通数组

a = [1,2,3,4]

index = a.index(3)

print(index) # output: 2

# Numpy数组

a2 = np.array([1,2,3,4])

index = np.where(a2 == 2)

print(index[0][0]) # output: 1