Efficient way to use if in python

Question

I'm a very beginner in python (I'm using python 3.7.4) and while coding, I can across a tedious situation while applying the condition in "if" statement as in the following code:

from array import *
ans = array('i')

for a in range(10):
    for b in range(10):
        for c in range(10):
             if a == 5 or b == 5 or c == 5:
                 ans.append(100 * a + 10 * b + c)

for x in ans:
    print(x)

To this I tried to attempt a solution by replacing the if- statement line as:

if (a or b or c) == 2:

But I miserably failed. Can anyone tell what this does? And can anyone provide me the best solution for my problem? I've shown an example of only one condition, whereas I've to put many of such conditions. Thank you for answering my query in advance!

Are you going to replace that simple condition with another ? — AmirHmZ, Apr 04 '20 at 07:25

score 2 · Answer 1 · answered Apr 04 '20 at 07:39

2

You can try to replace the following statement

if a == 5 or b == 5 or c == 5:

with

if 5 in [a, b, c]:

Please note that this might not work with all of the python types.

>>> a = 1
>>> b = 2
>>> c = 3
>>> 2 in [a, b, c]
True
>>> 4 in [a, b, c]
False

>>> a = [1]
>>> b = [2]
>>> c = [3]
>>> [3] in [a, b, c]
True
>>> 3 in [a, b, c]
False
>>> [4] in [a, b, c]
False

answered Apr 04 '20 at 07:39

Amiram

1,227
6
14

Make those braces curly to make a set. Also, that will reinitialize the list every time. – Mad Physicist Apr 04 '20 at 07:41
If it will be a `set` the second example with the `list` won't work and he will get an "TypeError: unhashable type: 'list'". – Amiram Apr 04 '20 at 07:43
I've never seen a list used as a search key. But I have seen a tuple being used for that. – Mad Physicist Apr 04 '20 at 07:49
That is `True` :) – Amiram Apr 04 '20 at 08:05

score -1 · Answer 2 · answered Apr 04 '20 at 07:48

-1

this will work for you ig

cond1=1
cond2=5
cond3=7
cond4=3

if (cond1 == 5 or cond2 == 5 or 
       cond3 == 5 or cond4 == 5) :
    print(cond1*cond4)

else :
    print("hello")

answered Apr 04 '20 at 07:48

raven404

1,039
9
14

Efficient way to use if in python

2 Answers2