How to check if a specific integer is in a list

Question

I want to know how to make an if statement that executes a clause if a certain integer is in a list.

All the other answers I've seen ask for a specific condition like prime numbers, duplicates, etc. and I could not glean the solution to my problem from the others.

• Akavall: If you need to check if a specific integer is in a list a lot, you are better of converting your list to a set, and check if the integer is in the set.

Answer 1

You could simply use the in keyword. Like this :

if number_you_are_looking_for in list:
 # your code here

For instance :

myList = [1,2,3,4,5]
if 3 in myList:
 print("3 is present")

Answer 2

Are you looking for this?:

if n in my_list:
 ---do something---

Where n is the number you're checking. For example:

my_list = [1,2,3,4,5,6,7,8,9,0]
if 1 in my_list:
 print 'True'

Answer 3

I think the above answers are wrong because of this situation:

my_list = [22166, 234, 12316]
if 16 in my_list: 
 print( 'Test 1 True' )
 else: 
 print( 'Test 1 False' ) 
my_list = [22166]
if 16 in my_list: 
 print( 'Test 2 True' )
else: 
 print( 'Test 2 False' )

Would produce: Test 1 False Test 2 True

A better way:

if ininstance(my_list, list) and 16 in my_list: 
 print( 'Test 3 True' )
elif not ininstance(my_list, list) and 16 == my_list: 
 print( 'Test 3 True' )
else: 
 print( 'Test 3 False' ) 

• datashaman: This answer is wrong. The first stanza produces: Test 1 False, Test 2 False, as one would expect intuitively from python. You should remove this answer, it makes no sense.
• R. Cox: 16 in [216] produces False; that is, @datashaman is correct; an int is not a string.

Answer 4

If you want to see a specific number then you use in keyword but let say if you have

list2 = ['a','b','c','d','e','f',1,2,3,4,5,6,7,8,9,0]

Then what you can do. You simply do this:

list2 = ['a','b','c','d','e','f',1,2,3,4,5,6,7,8,9,0]
for i in list2:
if isinstance(x , int):
 print(x)

this will only print integer which is present in a given list.

• Bruce Bookman: if isinstance(x , int): print(x) Should be? if isinstance(i , int): print(i)