[Python-checkins] bpo-41774: Add programming FAQ entry (GH-22402)

[Terry Jan Reedy]

https://github.com/python/cpython/commit/5b0181d1f6474c2cb9b80bdaf3bc56a78bf5fbe7
commit: 5b0181d1f6474c2cb9b80bdaf3bc56a78bf5fbe7
branch: master
author: Terry Jan Reedy <tjreedy at udel.edu>
committer: GitHub <noreply at github.com>
date: 2020-09-29T01:02:44-04:00
summary:

bpo-41774: Add programming FAQ entry (GH-22402)

In the "Sequences (Tuples/Lists)" section, add
"How do you remove multiple items from a list".

files:
A Misc/NEWS.d/next/Documentation/2020-09-24-15-35-13.bpo-41774.5IqdGP.rst
M Doc/faq/programming.rst

diff --git a/Doc/faq/programming.rst b/Doc/faq/programming.rst
index 4f4ea8b18176c..76ae4d260fad4 100644
--- a/Doc/faq/programming.rst
+++ b/Doc/faq/programming.rst
@@ -1164,6 +1164,21 @@ This converts the list into a set, thereby removing duplicates, and then back
 into a list.
 
 
+How do you remove multiple items from a list
+--------------------------------------------
+
+As with removing duplicates, explicitly iterating in reverse with a
+delete condition is one possibility.  However, it is easier and faster
+to use slice replacement with an implicit or explicit forward iteration.
+Here are three variations.::
+
+   mylist[:] = filter(keep_function, mylist)
+   mylist[:] = (x for x in mylist if keep_condition)
+   mylist[:] = [x for x in mylist if keep_condition]
+
+If space is not an issue, the list comprehension may be fastest.
+
+
 How do you make an array in Python?
 -----------------------------------
 
diff --git a/Misc/NEWS.d/next/Documentation/2020-09-24-15-35-13.bpo-41774.5IqdGP.rst b/Misc/NEWS.d/next/Documentation/2020-09-24-15-35-13.bpo-41774.5IqdGP.rst
new file mode 100644
index 0000000000000..af8e02437cb2b
--- /dev/null
+++ b/Misc/NEWS.d/next/Documentation/2020-09-24-15-35-13.bpo-41774.5IqdGP.rst
@@ -0,0 +1,2 @@
+In Programming FAQ "Sequences (Tuples/Lists)" section, add "How do you
+remove multiple items from a list".