print a string with alternating letters capitalized. IndexError string index out of range

Question

This code creates a IndexError that shows that i is out of range.

string = "Hello World"
string_empty = ""
length = len(string)

for i in range(0, length):
    string_empty += string[i]
    if i <= length:
        string_empty += string[i+1].upper()
  
print(f"alternate word capitalized: {string_empty}")

Answer 1

Why are you using indexes? You can just go through the characters themselves.

# 1 paragraph lorem ipsum from https://vlad-saling.github.io/star-trek-ipsum/
string = "We're acquainted with the wormhole phenomenon, but this... Is a remarkable piece of bio-electronic engineering by which I see much of the EM spectrum ranging from heat and infrared through radio waves, et cetera, and forgive me if I've said and listened to this a thousand times. This planet's interior heat provides an abundance of geothermal energy. We need to neutralize the homing signal."

def cap_letters(input_string: str) -> str:
    result = ""
    capitalize = True
    for c in input_string.lower():
        if capitalize:
            result += c.upper()
        else:
            result += c
        # only switch capitalization if it's a letter
        if c.isalpha():
            capitalize = not (capitalize)
    return result


print(f"alternate letter capitalized:\n{cap_letters(string)}\n")

output:

alternate letter capitalized:
We'Re AcQuAiNtEd WiTh ThE wOrMhOlE pHeNoMeNoN, bUt ThIs... Is A rEmArKaBlE pIeCe Of BiO-eLeCtRoNiC eNgInEeRiNg By WhIcH i SeE mUcH oF tHe Em SpEcTrUm RaNgInG fRoM hEaT aNd InFrArEd ThRoUgH rAdIo WaVeS, eT cEtErA, aNd FoRgIvE mE iF i'Ve SaId AnD lIsTeNeD tO tHiS a ThOuSaNd TiMeS. tHiS pLaNeT's InTeRiOr HeAt PrOvIdEs An AbUnDaNcE oF gEoThErMaL eNeRgY. wE nEeD tO nEuTrAlIzE tHe HoMiNg SiGnAl.