if statement to check list items

Question

I have the following list and variable:

x = [1,2,17,4,5,7,11]
v = 18

and I want (in a single if statement) to search in the list to check if it contains an item that if we subtract "or any other operation" it from v variable will equal to one "as example".

For the above example, the if statement will yield True since we have the item 18 (18-17=1).

Can we do that in a single if statement (without using a separate loop) with python ?

"I have X and I *want* Y" is a work assignment, not a question. Work assignments are things you give your employees. — Tomalak, Mar 30 '18 at 11:41
@MIBMinion First you say ‘*subtract it from v*’ then you use `18 - 17` as an example. Which one should be subtracted from which? — Biffen, Mar 30 '18 at 11:42
@Biffen, as example , any operation allowed .. the idea is to check the values in the if statement with a loop — Minions, Mar 30 '18 at 11:48

score 3 · Answer 1 · edited Mar 30 '18 at 12:42

3

You can get a list of answers out with a list comprehension that uses if statement:

x = [1,2,18,4,5,7,11]
v = 17
answers = [i for i in x if i-v==1]
print(answers) # [18]

edited Mar 30 '18 at 12:42

baduker

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answered Mar 30 '18 at 11:45

yoyoyoyo123

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score 3 · Accepted Answer · answered Mar 30 '18 at 11:45

3

The correct answer to your question is already in comments, but assuming you tried to make your example more minimal to hide a more complicated question (one where the operation for which you substituted subtraction is not invertible), you can do this in Python with the any function and a list comprehension:

x = [1,2,18,4,5,7,11]
v = 17
if any([a - v == 1 for a in x]):
    print("Found it!")

answered Mar 30 '18 at 11:45

Mees de Vries

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I gave a different answer but this one is great. any/all built-ins are so underrated. – yoyoyoyo123 Mar 30 '18 at 11:52
Thanx, that's what I want .. – Minions Mar 30 '18 at 12:09

if statement to check list items

2 Answers2