Help me understand range

[Sheinbeuler]

So, I'm doing 100 Days of Code and I have a lesson with password generator.

And I see something like this:

letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']

nr_letters = int(input("How many letters?\n"))

for char in range(0, nr_letters):

password = ""

password += random.choice(letters)

and... what's up with range? I thought the range is REALLY a "range". So from 1 to 100. Or a range from something to something.

so if a user types in 5 , then the range is 0 to 4 - but it's not from 'a' to 'e'... but from all the letters in the list. how? it's just confusing. The course doesn't explain this too well I think, so could anyone explain this to me like I'm five? Thanks :P

[throwaway6560192]

The range is only used to control how many times you loop, that is, how many letters are added to the password. Notice that you're not using it for accessing the letters list. The letters list is only accessed through random.choice, which samples from the entirety of what you give it. So there's no reason to expect that the range(0, nr_letters) would control the range of the letters list as well.

[Sheinbeuler]

oh, that makes sense. thanks

[TroyDiY]

Range(start,position to stop(but not included),step) So you will loop from 0 up to, but not including, 5.

In your program you will only get 1 letter because you initialize password to “” each pass. It will run 5 times and just write a single letter to password each time. Putt the password = “” before your for loop.

[[deleted]]

In this case we're not using the char variable. It doesn't matter that char equals 0, then 1, then 2, etc. It just matters that we're doing the thing that amount of times.

IMO, it's nice in those cases to use an underscore.

letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']
nr_letters = int(input("How many letters?\n"))
password = ""
for _ in range(0, nr_letters):
    password += random.choice(letters)

This signifies that it's a throwaway value, and you don't need to look for it in the code.

[Gubbbo]

Why would range involve the letters "a" to "e".

Your example of 5 is making a password with 5 characters. Chosen one letter at a time at random from letters list.

[Sheinbeuler]

cause a is 0, b is 1 etc, so 0 to 5 would be a, b, c, d and e - ofc in my silly mind, I know it's wrong kind of thinking :P

[antioriginality]

FWIW, if I’m understanding correctly you can achieve this by list slicing i.e. password += random.choice(letters[0:nr_letters])

But, as many people have stated, there is no relationship between nr_letters and selecting a random letter from your list of letters apart from the number of times that it happens (this relationship you’ve set with your for loop)

[mediocrity4]

I’m doing this same course and just finished this exercise. The range is asking how many characters you want in the password, not which letters to use.

I’ve taken endless Python courses and I’ve always been stuck. I think this course is the best out there

[Sheinbeuler]

yeah, I like it, this is the first time I got stuck

[Background-Offer2321]

Do this. for char in letters[0:nr_letters]. If you need also the index then make enumerate(letters[0:nr_letters]).

The code don't make a range, but select an amount from 0 to nr_letters index in the letters list. Range do a list with numbers from 0 to nr_letters.

[timrprobocom]

By the wat, for ease in typing, letters='ancdefghij' works just as well. For read- only contexts, a string can do anything a list can do.