Python sort function sort () differs from sorted ()

Sort is the function of the container: sort (Cmp=none, Key=none, Reverse=false)

Sorted is a python built-in function: Sorted (iterable, Cmp=none, Key=none, Reverse=false)

Parameter resolution:

CMP: compare function, compare what parameter is determined by key. For example: CMP (E1, E2) is a comparison function with two parameters, the return value: Negative (E1 < E2), 0 (e1 = = E2), positive (E1 > E2).
Key: Use a property or function of the list element as the keyword.
Reverse: Collation, you can choose True or false.
Sorted one more parameter iterable: The container of the iteration type to be sorted

Example 1:

>>> a=[1,2,5,3,9,4,6,8,7,0,12]
>>> A.sort ()
>>> A
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 12]

>>> a=[1,2,5,3,9,4,6,8,7,0,12]
>>> Sorted (a)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 12]
>>> A
[1, 2, 5, 3, 9, 4, 6, 8, 7, 0, 12]

Difference:

For an unordered list of a, call A.sort () and return the A,sort () function after a is sorted to modify the contents of the list to be sorted.

For the same unordered list A, call sorted (a), a is sorted and a new list is returned, and a has no effect on a.

Example 2:

Suppose you use tuples to hold information about each student, including the number, name, and age. Use the list to save information for all students.

>>> list1=[(8, ' Logan ', +), (2, ' Mike '), (5, ' Lucy ', 19)]
>>> List1.sort ()
>>> List1
[(2, ' Mike ', '), (5, ' Lucy ', '), (8, ' Logan ', 20)]

>>> list1=[(8, ' Logan ', +), (2, ' Mike '), (5, ' Lucy ', 19)]
>>> Sorted (List1)
[(2, ' Mike ', '), (5, ' Lucy ', '), (8, ' Logan ', 20)]
>>> List1
[(8, ' Logan ', '), (2, ' Mike ', '), (5, ' Lucy ', 19)]

Summary: As the example shows, when the list is made up of lists (or tuple), by default, sort and sorted are sorted according to List[0] (or tuple[0]) as the sorted key.

These are the default sorting methods, and we can write code to control the sorting behavior of the two functions. There are three main ways: Based on key function, CMP function and based on reverse function

1) Sort based on key function

>>> list1=[(8, ' Logan ', +), (2, ' Mike '), (5, ' Lucy ', 19)]
>>> List1.sort (Key=lambda x:x[2])
>>> List1
[(5, ' Lucy ', +), (8, ' Logan ', '), (2, ' Mike ', 22)]

>>> list1=[(8, ' Logan ', +), (2, ' Mike '), (5, ' Lucy ', 19)]
>>> Sorted (List1, Key=lambda x:x[2])
[(5, ' Lucy ', +), (8, ' Logan ', '), (2, ' Mike ', 22)]
>>> List1
[(8, ' Logan ', '), (2, ' Mike ', '), (5, ' Lucy ', 19)]

2) based on CMP functions

>>> list1=[(8, ' Zogan ', +), (2, ' Mike '), (5, ' Lucy ', 19)]
>>> List1.sort (Cmp=lambda x,y:cmp (x[1],y[1]))
>>> List1
[(5, ' Lucy ', +), (2, ' Mike ', '), (8, ' Zogan ', 20)]

>>> list1=[(8, ' Zogan ', +), (2, ' Mike '), (5, ' Lucy ', 19)]
>>> Sorted (List1, Cmp=lambda x,y:cmp (x[1],y[1]))
[(5, ' Lucy ', +), (2, ' Mike ', '), (8, ' Zogan ', 20)]
>>> List1
[(8, ' Zogan ', '), (2, ' Mike ', '), (5, ' Lucy ', 19)]

3) based on reverse function

>>> a=[1,2,5,3,9,4,6,8,7,0,12]
>>> A.sort (Reverse=false)
>>> A
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 12]

>>> a=[1,2,5,3,9,4,6,8,7,0,12]
>>> A.sort (reverse=true)
>>> A
[12, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
>>> A.sort (reverse=true)

Summary: Reverse=false is sorted in ascending order; Reverse=true is sorted in descending order

Python sort function sort () differs from sorted ()