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Python

Posted by Dean Brittain
Dean Brittain
626 Points

Capitalizing every other letter in a string -- Explain in detail?

I know that this works.. but I don't know how and why it works. If someone can break this down for me, I'd really appreciate it. 

def spongebob(string):
    new_quote = ""
    i = True  # capitalize
    for char in string:
        if i:
            new_quote += char.upper()
        else:
            new_quote += char.lower()
        if char != ' ':
            i = not i
    return new_quote
print(spongebob("That's not how you do that!"))

1 Answer

Dave StSomeWhere
Dave StSomeWhere
19,870 Points

Does adding some comments and print statements help to explain the processing - Try testing some different scenarios. Also notice that the function handles spaces but doesn't do anything with the apostrophe in your sample - I just used small strings to keep it short.

Here's the code:

def spongebob(string):
    # Initialize new quote to an empty string
    new_quote = ""
    # Initialize i to True - do the char.upper() method
    i = True  # capitalize
    # Loop the passed in string
    for char in string:
        print('Begin of loop, i is {}, char is {} and the new quote is {}'.format(i, char, new_quote))
        # When i is true set to upper
        if i:
            # append the upper case character
            new_quote += char.upper()
        # When i is false set to lower
        else:
            # append the lower case character
            new_quote += char.lower()
        # Skip if the char is a space
        if char != ' ':
            # Toggle i - to impact the upper/lower if above
            i = not i
    print("\nAfter Loop, i is {} and the new quote is {}\n".format(i, new_quote))
    return new_quote


print('Run 1 result --->' + spongebob("A B CD"))
print("\nOne More time")
print('Run 2 result --->' + spongebob("a b cd"))


# outputs
Begin of loop, i is True, char is A and the new quote is 
Begin of loop, i is False, char is   and the new quote is A
Begin of loop, i is False, char is B and the new quote is A 
Begin of loop, i is True, char is   and the new quote is A b
Begin of loop, i is True, char is C and the new quote is A b 
Begin of loop, i is False, char is D and the new quote is A b C

After Loop, i is True and the new quote is A b Cd

Run 1 result --->A b Cd

One More time
Begin of loop, i is True, char is a and the new quote is 
Begin of loop, i is False, char is   and the new quote is A
Begin of loop, i is False, char is b and the new quote is A 
Begin of loop, i is True, char is   and the new quote is A b
Begin of loop, i is True, char is c and the new quote is A b 
Begin of loop, i is False, char is d and the new quote is A b C

After Loop, i is True and the new quote is A b Cd

Run 2 result --->A b Cd
Dean Brittain
Dean Brittain
626 Points

You really must be a St. Thank you. This completely helps me understand.