python always returns if statement as true if i use or

Question

I'm relatively new to programming, and while i was making a simple scanner that runs a command whenever it finds a forward-slash (/) or a back-slash (\), it outputs things that (i think) it shouldn't be outputting.

here is the code:

loop = 0
a = 'm/es\s/a/ge'
while loop <= len(a)-1:
    if a[loop] == '/' or '\\':
        print ('found at: ' + str(loop))
    loop += 1

This outputs:

found at: 0
found at: 1
found at: 2
found at: 3
found at: 4
found at: 5
found at: 6
found at: 7
found at: 8
found at: 9
found at: 10

when it should only print anything 4 times (as there is only 4 slashes in the string)

I tried removing "or" along with the other possible value, and it did what it should, so the problem must be with the "or"

am I using "or" wrong? or is this something else?

EDIT: I tried How do I test one variable against multiple values?, but that question is asking how to test multiple variables against a single value, while I need to know how to test a single variable against multiple possible values

You can't use `or` like that. it's not `if a == 1 or 2` it's `if a == 1 or a == 2` Or simpler : `if a in [1, 2]` — Loïc, Sep 18 '16 at 04:25
re-read the duplicate question, it applies to your `if a[loop] == '/' or '\\':` statement. — Dan Cornilescu, Sep 18 '16 at 14:22

score 1 · Accepted Answer · answered Sep 18 '16 at 04:23

1

You want to use

if a[loop] == '/' or a[loop] == '\\'

else the '\\' will always return true.

answered Sep 18 '16 at 04:23

user3145912

131
1
15

Mehrdad Dadvand · Answer 2 · 2016-09-18T04:33:34.823

0

You have to use this in your condition statement:

If a[loop] =='/' or a[loop]=='\\':

edited Sep 18 '16 at 04:33

answered Sep 18 '16 at 04:27

Mehrdad Dadvand

340
4
19

python always returns if statement as true if i use or

2 Answers2