How to execute code if a variable has a certain value?

Question

I have a problem with my code. The language is python. I am trying to use an if statement to execute some code if a variable has a certain value.

op = 5

if(op = 5):
    print("op is 5!")

Every time I run this program, it gives me a syntax error. I have tried doing this instead;

op = 5

if op = 5:
    print("op is 5!")

But it still gives me the error. I am asking this question because I am doing a calculator project and need this.

You cannot have an assignment statement inin place of the Boolean condition of an if statement. — Prune
– Prune, Commented Aug 23, 2020 at 20:24
@Prune not technically true now that there are assignment expressions. i.e. walrus operator :=. Edit: Actually I guess you said statement so you are still correct — flakes
– flakes, Commented Aug 23, 2020 at 20:25
Make sure to include the actual error message in question, formatted appropriately. In this case the ^ points to the exact part of the expression (unfortunately Python doesn't have a super clear diagnostic message which is certainly could in this case). — user2864740
– user2864740, Commented Aug 23, 2020 at 20:26

Mureinik · Accepted Answer · 2020-08-23 20:24:12Z

4

= is the assignment operator. You're looking for the equality check operator, ==:

if op == 5:
    print("op is 5!")

answered Aug 23, 2020 at 20:24

Mureinik

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1 Comment

@therealemg If this answers your question please mark it correct for future readers :)

mrwolferinc · Accepted Answer · 2020-08-23 20:32:57Z

1

The equality check operator is ==. You put the assignment operator, which is this: =.

The following code will return a SyntaxError:

foo = input('Enter the value of foo: ')
if foo = '5':
    print('foo is equal to 5!')
else:
    print('foo is not equal to 5!')

But this won't:

foo = input('Enter the value of foo: ')
if foo == '5':
    print('foo is equal to 5!')
else:
    print('foo is not equal to 5!')

You just need to change the operator in the if statement to ==.

answered Aug 23, 2020 at 20:32

mrwolferinc

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ashish · Accepted Answer · 2020-08-23 21:28:47Z

1

For comparison we used double equal sign ==

Not single

if op == 5:
    print("op is 5!")

answered Aug 23, 2020 at 21:28

ashish

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