Python Learning note __4.1.3 sorted

# This is a learning note for the Liaoche teacher Python tutorial

1 , overview

The python built-in sorted () function can sort the list.

The sorted () function is also a high-order function that can receive a key function to implement a custom sort, and the function specified by key will be applied to each element of the list and sorted according to the result returned by the key function.

# Direct Sort

>>> Sorted ([36, 5,-12, 9,-21])

[-21,-12, 5, 9, 36]

# Accept the key function sort

>>> sorted ([5, -12, 9, -21], key=abs)

[5, 9,-12,-21, 36]

# Sort by alphabetical order

>>> sorted ([' Bob ', ' about ', ' Zoo ', ' credits '], Key=str.lower) # sorted by default is ASCII sorted, and z>a, so need to add key function

[' About ', ' Bob ', ' credits ', ' Zoo ']

2 , examples

1,Suppose we use a group of tuples to represent student names and scores:L = [(' Bob ', the), (' Adam ', the), (' Bart ', the), (' Lisa ', the)]

Please use Sorted () The above list is sorted by name, respectively:

#-*-Coding:utf-8-*-

L = [(' Bob ', ', '), (' Adam ', ' the '), (' Bart ', ' the '), (' Lisa ', 88)]

# Sort by name

def by_name (t):

return t[0]

# Sort by score. -t[1], the higher thescore, the smaller the minus sign, the more forward

def by_score (t):

RETURN-T[1]

# Test

L2 = sorted (L, Key=by_name)
Print (L2)

# Sort by name

[(' Adam ', the "," (' Bart '), (' Bob ', '), (' Lisa ', 88)]

# Sort by score

[(' Adam ', "the"), (' Lisa ', ","), (' Bob ', '), (' Bart ', 66)]

Python Learning note __4.1.3 sorted