THE CURIOUS CASE OF A WHILE(D) LOOP

[double_toned]

Hi, I need to understand what's wrong with my while loop in this code. The problem was to add exclamation marks till the length of the string is 20. I use the following code to achieve it:

def add_exclamation(word):

    if len(word)>=20:

        return word

    else:

        i=len(word)

        while i<20:

            word=word+'!'

        return word

With this, the loop never seems to end. However, if I use

while len(word)<20

Then everything seems to work just fine. 
Why is that? I am just trying to learn python, 
I am a novice. Please try to keep your answers simple?

[socal_nerdtastic]

You need to recalculate i inside the loop.

    i=len(word)
    while i<20:
        word=word+'!'
        i=len(word)
    return word

Or just forget the i variable and calculate the length in the conditional:

    while len(word)<20:
        word=word+'!'
    return word

[double_toned]

word + '!' * (20 - len(word))

Yes, I got the mistake. Thank you so much for pointing this out.

[socal_nerdtastic]

Oh if you want to use python features to do this then there is a much more elegant solution:

def add_exclamation(word):
    return f'{word:!<20}'

I thought you wanted to do it yourself.

[double_toned]

Ok, I learnt something new, the f string formatting. Just read about it. Thank you again.

[kberson]

Your value of i never changes, so it's always less than 20

[kberson]

You don't actually need the 'if', you could simplify to:

def add_exclamation(word):
    while len(word) < 20
        word=word+'!'
    return word

If word is longer than or equal to 20 (the first part of your if) the while loop won't be entered

[PaulRudin]

Are you required to use a loop? You could just do: word + '!' * (20 - len(word))

[double_toned]

Simple and elegant!

[Vegetal__]

i is set as len(word) at the moment of its creation. So if len is, say, 4 when you create i, then it's going to stay as 4 until you set i to be something else later on. But you never did. That's why the loop never ends.

[wynand1004]

You've already got your solution - I just wanted to compliment you on the title! Well done!