Python filter function filter () uses a custom function to filter sequence instances, pythonfilter

Python filter function filter () uses a custom function to filter sequence instances, pythonfilter

Filter function:

The filter () function can filter a sequence. That is to say, you can use a custom function to filter a sequence and upload each of the sequences to a custom filter function for processing, filter the returned results. The filtered results are returned at a time.

The filter () function has two parameters:

First, the custom function name, required
Second, the columns to be filtered are required.

DEMO

Requirement: filter the number of values greater than 5 and less than 10:
Copy codeThe Code is as follows:
# Coding = utf8
# Define functions greater than 5 and less than 10
Def guolvhanshu (num ):
If num> 5 and num <10:
Return num
 
# Define a sequence
Seq =)
 
# Use the filter function
Result = filter (guolvhanshu, seq)
 
# (8, 9, 6)
Print result

Execution result:
Copy codeThe Code is as follows:
(8, 9, 6)

Because 8, 9, 6 is greater than 5, less than 10, it is filtered out.

How to Use the filter () function in python? Especially when a function has multiple input parameters

Map is to put the function call result in the list to return, it can also accept multiple iterable, in the n call function, will use iterable1 [n], iterable2 [n],... as a parameter.

Filter (function, iterable)
This function filters out all elements in iterable that return True or bool (Return Value) as True when calling the function using the element itself as a parameter and returns the result in a list.

Def f_large_than_5 (x ):
Return x> 5

Filter (f_large_than_5, range (10 ))

> [6, 7, 8, 9]

Python program, filter function, 27 environment and 31 environment are different

3. x returns an iter obj. If you want to return [], add list ()

>>> List (filter (bigger_than_five, [1, 10])
[6, 7, 8, 9, 10]

In fact, in 3.x, the simplest way to achieve your goal is directly:
>>> [X for x in range (11) if x> 5]
[6, 7, 8, 9, 10]