Elif or If; that is my question.

Hello! I've recently started out with Python, and I want to know more about elif and if statements. I'm confused by which is more appropriate at one time so you can successfully speak to the computer. Could you give me some examples of when you would use elif over if and vice versa? Thank you DEV community!

Comments

[Prateik Lohani]

both if and elif statements are used to check if a condition is true or not, but there is a subtle difference in usage.

Let's take the following structure:

s = "noice"
if(s[0] == "n"):
    print("first")
elif(s[1] == "o"):
    print("second")

Now here, the output will be:
first

Why? That's because when the if condition becomes True, we no longer need to check for the elif condition (which is basically else if in C if you've coded in C).

Now if the structure would've been this:

s = "noice"
if(s[0] == "n"):
    print("first")

# Notice that this is an if instead of an elif
if(s[1] == "o"):
    print("second")

The output would've been:
first
second

That's because now we are checking for BOTH the if conditions.
When you use elif with if, you essentially bond them together such that only ONE OF THEM WILL EXECUTE (if none of them does, it's recommended to keep an else statement too).

But when using multiple ifs together, python will check for each condition, because they are essentially different and not bonded together.

I hope that clears things out!

[Shawn]

Oh! That makes a lot more sense! So putting elif and if statements together means that it's confusing replit and making it to where it doesn't understand what to print. That helps me a ton! Thank you!

[Alexey Kinev]

Using of elif is needed when checks should be mutually exlusive.

You might also want to look into match .. case operators:

match parameter:
    case pattern1:
        # code for pattern 1
    case pattern2:
        # code for pattern 2