Python List sort()用法及代码示例

列出 sort() 方法

sort() 方法用于对列表元素进行升序和降序排序，该方法用这个列表(其元素要排序)调用并接受一些可选参数(在参数下面解释)，该方法不返回任何值，它对这个列表进行排序。

用法:

    List_name.sort(reverse=True|False, key=function)

参数：

• reverse=True|False– 这是一个可选参数，默认值为False，按升序对列表元素进行排序，如果设置为True，则按降序对列表元素进行排序。
• key=function– 它也是一个可选参数，可用于指定排序条件。

返回值：

这个方法的返回类型是<class 'NoneType'>，它什么都不返回。

示例 1：不指定任何参数的排序列表

# Python List sort() Method with Example

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

# printing the list
print("cars before sort operation...")
print("cars:", cars)

# sorting the elements
cars.sort() # sorts in ascending order

# printing the list
print("cars after sort operation...")
print("cars:", cars)

输出

cars before sort operation...
cars: ['BMW', 'Porsche', 'Audi', 'Lexus', 'Audi']
cars after sort operation...
cars: ['Audi', 'Audi', 'BMW', 'Lexus', 'Porsche']

示例 2：指定第一个参数的排序列表

# Python List sort() Method with Example

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

# printing the list
print("cars before sort operation...")
print("cars:", cars)

# sorting the elements specifying reverse=True
cars.sort(reverse=True) 

# printing the list
print("cars list elements in descending order...")
print("cars:", cars)

# sorting the elements specifying reverse=False
cars.sort(reverse=False) 

# printing the list
print("cars list elements in ascending order...")
print("cars:", cars)

输出

cars before sort operation...
cars: ['BMW', 'Porsche', 'Audi', 'Lexus', 'Audi']
cars list elements in descending order...
cars: ['Porsche', 'Lexus', 'BMW', 'Audi', 'Audi']
cars list elements in ascending order...
cars: ['Audi', 'Audi', 'BMW', 'Lexus', 'Porsche']

示例 3：指定两个参数的排序列表

# Python List sort() Method with Example

# defining a function that will return length
def getLen(e):
    return len(e)
    
# declaring the list
cars = ["BMW", "Porsche", "Audi", "Lexus", "Audi"]

# printing the list
print("cars before sort operation...")
print("cars:", cars)

# sorting the elements specifying reverse=True
cars.sort(reverse=True,key=getLen) 

# printing the list
print("cars list elements in descending order based on length...")
print("cars:", cars)

# sorting the elements specifying reverse=False
cars.sort(reverse=False,key=getLen) 

# printing the list
print("cars list elements in ascending order based on length...")
print("cars:", cars)

输出

cars before sort operation...
cars: ['BMW', 'Porsche', 'Audi', 'Lexus', 'Audi']
cars list elements in descending order based on length...
cars: ['Porsche', 'Lexus', 'Audi', 'Audi', 'BMW']
cars list elements in ascending order based on length...
cars: ['BMW', 'Audi', 'Audi', 'Lexus', 'Porsche']