Python List pop()用法及代码示例

列出 pop() 方法

pop() 方法用于从列表中删除指定索引/位置处的元素，使用此列表(我们必须从中删除元素的列表)调用该方法，并将索引作为参数提供。

用法:

    list_name.pop(index)

参数：

• index– 它是一个可选参数，它表示列表中的索引，我们必须删除该元素。如果我们不提供该值，则默认值为 -1，表示最后一项。

返回值：

这个方法的返回类型是元素的类型，它返回被移除的元素。

范例1：

# Python List pop() Method with Example

# declaring the list
cars = ["BMW", "Porsche", "Audi", "Lexus", "Audi"]

# printing the list
print("cars before pop operations...")
print("cars:", cars)

# removing element from 2nd index
x = cars.pop(2)
print(x,"is removed")

# removing element from 0th index
x = cars.pop(0)
print(x,"is removed")

# printing the list 
print("cars before pop operations...")
print("cars:", cars)

输出

cars before pop operations...
cars: ['BMW', 'Porsche', 'Audi', 'Lexus', 'Audi']
Audi is removed
BMW is removed
cars before pop operations...
cars: ['Porsche', 'Lexus', 'Audi']

范例2：

# Python List pop() Method with Example

# declaring the list
x = [10, 20, 30, 40, 50, 60, 70]

# printing the list
print("x before pop operations...")
print("x:", x)

res = x.pop(0)   # will remove 0th element
print(res,"is removed")

res = x.pop()   # will remove last element
print(res,"is removed")

res = x.pop(-1)   # will remove last element
print(res,"is removed")

# printing the list
print("x after pop operations...")
print("x:", x)

输出

x before pop operations...
x: [10, 20, 30, 40, 50, 60, 70]
10 is removed
70 is removed
60 is removed
x after pop operations...
x: [20, 30, 40, 50]

如果索引超出范围，"IndexError" 将返回。

范例3：

# Python List pop() Method with Example

# declaring the list
x = [10, 20, 30, 40, 50, 60, 70]

# printing the list
print("x before pop operations...")
print("x:", x)

res = x.pop(15) # will return an error
print(res," is removed")

# printing the list
print("x after pop operations...")
print("x:", x)

输出

x before pop operations...
x: [10, 20, 30, 40, 50, 60, 70]
Traceback (most recent call last):
  File "main.py", line 10, in <module>
    res = x.pop(15) # will return an error
IndexError:pop index out of range