python3 Learning notes -- Two sort methods

• List sorting method
• sort()
• sorted()

List sorting method

• sort()： Only on list Object to sort , Will change list Self order , no return value , namely In situ sorting
• sorted()： Sort all iteratable objects , Return the sorted new object , The original object remains unchanged ;

sort()

list.sort(key=None, reverse=False)

• key： Set sorting method , Or specify list Elements used for sorting in ;
• reverse： Ascending descending order , The default is ascending ;

Example ：

nums = [2, 3, 5, 1, 6]
nums.sort()
print(nums) # [1, 2, 3, 5, 6]
nums.sort(key=None, reverse=True)
print(nums) # [6, 5, 3, 2, 1]
students = [('john', 'C', 15), ('jane', 'A', 12), ('dave', 'B', 10)]
students.sort(key=lambda x: x[2]) # Sort by the third element in the list 
print(students) # [('dave', 'B', 10), ('jane', 'A', 12), ('john', 'C', 15)]

sorted()

sorted(iterable [, key[, reverse]])

• key ： Set sorting method , Or specify in the iteration object , Elements for sorting ;
• reverse ： Ascending descending order , The default is ascending ;

Example ：

nums = [2, 3, 5, 1, 6]
newNums = sorted(nums)
print(nums) # [2, 3, 5, 1, 6]
print(newNums) # [1, 2, 3, 5, 6]
students = [('john', 'C', 15), ('jane', 'A', 12), ('dave', 'B', 10)]
newStudents = sorted(students, key=lambda x: x[1])
print(students) # [('john', 'C', 15), ('jane', 'A', 12), ('dave', 'B', 10)]
print(newStudents) # [('jane', 'A', 12), ('dave', 'B', 10), ('john', 'C', 15)]