Splitting a word at the uppercase without using regex or a function leads to error cannot assign the expression or not enough value to unpack

Question

I am trying to learn python. In this context I need to split a word when encountering an upper case, convert it as a lower case and then insert a "_".

I have seen various quite complex answer here or here or here, but I am trying to do it as simply as possible.

So far, here is my code:

word = input("What is the camelCase?")

for i , k in word:
    if i.isupper() and k.islower():
        word2 = k + "_" + i.lower + k
        print(word2)
    else:
        print(word)

This leads to "not enough values to unpack (expected 2, got 1)" after I input my word.

Another attempt here:

word = input("What is the camelCase?")

for i and k in word:
    if i.isupper() and k.islower():
        word2 = k + "_" + i.lower + k
        print(word2)
    else:
        print(word)

In this case I cannot even write my word, I directly have the error: "cannot assign to expression"

Answer 1

Try it this way.

a=input("enter word:")
b=""
for i in a:
    if i.isupper():
        b=b+(i.lower()+"_")
    else:b=b+i
print(b)

Hope it helped :)

Answer 2

I suspect the problem is that for i, k in word: is iterating over the characters of the string, and trying to unpack it into two variables.

This does not work as the characters are not tuples, so it fails to unpack.

The expression i and k in for i and k in word: is a boolean expression and not a variable. It is trying to assign each character in word to the boolean expression i and k, which fails.