so ill post a few of my failed examples below along with what I came up with as a fix, and then the actual correct code. I feel like im so close to grasping this, but missing some logic. this is for a hangman game.
one of the failed attempts:
import random
word_list = ["aardvark", "baboon", "camel"]
chosen_word = random.choice(word_list)
#Testing code
print(f'Pssst, the solution is {chosen_word}.')
#Create an empty List called display.
#For each letter in the chosen_word, add a "_" to 'display'.
#So if the chosen_word was "apple", display should be ["_", "_", "_", "_", "_"] with 5 "_" representing each letter to guess.
display = ["_"] * len(chosen_word)
guess = input("Guess a letter: ").lower()
#If the letter at that position matches 'guess' then reveal that letter in the display at that position.
#e.g. If the user guessed "p" and the chosen word was "apple", then display should be ["_", "p", "p", "_", "_"].
for letter in chosen_word:
if guess == letter:
for i in range(len(chosen_word)):
display.insert(i, guess)
print(display)
second:
for letter in chosen_word:
if guess == letter:
for i in range(len(chosen_word[letter])):
display.insert(i, guess)
I ended up just saying screw it and went to this:
display = []
for char in chosen_word:
if guess == letter:
display += letter
else:
display += "_"
correct way of doing it:
import random
word_list = ["aardvark", "baboon", "camel"]
chosen_word = random.choice(word_list)
print(f'Pssst, the solution is {chosen_word}.')
display = []
word_length = len(chosen_word)
for _ in range(word_length):
display += "_"
print(display)
guess = input("Guess a letter: ").lower()
for position in range(word_length):
letter = chosen_word[position]
if letter == guess:
display[position] = letter
print(display)
so as you can see, i get that I can grab specific parts of a list using indices or slices, but somewhere in my brain my logic is wrong. if you guys have struggled with this before or if you have a good youtube video to help me break it down id be beyond thankful!
I think you’re misunderstanding the
insert
method.insert
keeps everything that was already in the list, including the item at the given index. it just shifts part of it to the right to make room for the thing you’re inserting. Directly changing the list usingdisplay[position] = letter
instead replaces the item at the index withletter
.Does that make sense?
Yeah I figured that one out from the documentation. I with I saved more of my trial and errors so I could show you guys what I needed help with better. I tried the list.insert(x) and then I would do a list.pop(i+1) as well 😂
I guess what I need help with is I keep messing up where I would put "for x in y: z= y [in position z]
Instead of blindly trying code until it works I would suggest you to write on paper the distinct steps that are required to solve the problem.
Imagine you are the computer and you can do nothing else but what Python allows you. How do you solve the problem ?
Usually people do this exercise on a small example. Then they generalise the approach when they find examples where it does not work.
Ahhh you know what. This would help me. Because when I’m stumped, I’m definitely just “blindly” trying different orders of things and getting frustrated. Thank you very much for the tip
Yeah sometimes you just have to take a step back and think again. Then you will think more clearly and actually know what you wrote :) good luck!
Having the output of each thing you tried would help us get a feel for where your code was messing up without us having to run it ourselves to get the output.
That said, for code snippet 1, you’re inserting the letter instead of replacing the underscore with the letter. Not only that, but your for-loop essentially does the following:
- loop over the length of
chosen_word
- if
guess
is in the above loop- iterate over the
display
array and addguess
that many times (effectively doubling the `display array)
- iterate over the
Your second code snippet does the same thing, but with actual formatting so that Python could run the code.
I believe your third code snippet introduces
char
but then returns toletter
. It might work if you replacedchar
withletter
again. Also+= letter
will add the letter to the end ofdisplay
, which is not what you want to do.I did my own version of Hangman in Python a couple years ago if you want to look at the code and see what I did. I’m just a hobbyist, so it’s not fantastic, but it might give you an idea of how someone else has approached the problem.
- loop over the length of
Don’t forget Python’s amazing list comprehension syntax!
guess = input(“Guess a letter:”).lower() display = [ letter if letter == guess else “_” for letter in word ]
Just one part of your question, but it saves a lot of futzing around with indices and
replace
s.Even as an experienced python dev I sometimes prefer explicit for loops over list comprehensions. I think for people who didn’t even grasp the concept of a for loop they are more confusing than helping.
Yeah, I’m not a fan of them overall. I think multiple lines is more readable. There are a LOT of people that disagree with me though.
I thought I was the only one… to me unless it’s a super-simplistic comprehension, it has a similar effect as when C programmers write
if (xx = !(1 == (a ? !c : 34 ^ blit_target))) {
. Congratulations, you fit it all on one line! At the expense of totally destroying my train of thought when I’m trying to scan down the code and figure out what the hell’s going on. Well done.
I think what tripped you up here is that you iterated over the wrong object. In your second solution:
for letter in chosen_word: if guess == letter: for i in range(len(chosen_word[letter])): display.insert(i, guess)
while in the correct solution:
for position in range(word_length): letter = chosen_word[position] if letter == guess: display[position] = letter
The most important difference here is that in your code block, you iterate over the letters, ie.
'a', 'a', 'r', ...
, while in the second you iterate over the numerical indices of the string,0, 1, 2, ...
. In this specific use case, it’s much easier to use the numerical indices - because you can see how the second code block is usingposition
in two places - once to retrieve the letter from the solution, and then again to update the display when theif
condition matches.Usually we prefer iteration using the method you used in your solution. But in this case, it’s easier to just iterate by index because you’re retrieving the element from one string, and updating the same position in the other string. You have no way of knowing what position to modify in
display
unless you have the numerical position, so it’s much easier to iterate that way in this case.This is a pretty compact and - I think - easy to read way of doing it:
while(display != list(chosen_word)):
guess = input("Guess a letter: ").lower()
display = list(map(lambda c, d: c if d != '_' or c == guess else d, chosen_word, display))
print(display)
print("Congrats! You did it!")
Mapping over an array is a pretty powerful tool and also using ternary expressions. If you’re not familiar, a map basically just iterates over an array and runs a function on that item, replacing it with whatever the return value of the function is.
For example:
ones = [1, 1] twos = list(map(lambda n: n + 1, ones))
It’s running the lambda function with n as a parameter and returning n + 1, and it’s pulling the numbers from the array “ones”.
Then ternary expressions I also find quite powerful. The format of which is basically:
(result if true) if (condition to check) else (result of false)
Or:
2 if 1 + 1 == 2 else "You broke math. How did you do that?"
Based on the first example:
If you want to help yourself a bit,
enumerate
your for loop. enumerate turns an iterable (like a list, or in this case a string) into an iterable of tuples, with contents being an int representing the index of an item and the item itself:for (i, letter) in enumerate(chosen_word):
(Side note, the parenthesis surrounding
(i, letter)
are optional. I purposely included them to show that it’s a tuple.)i
will be the index of each character, andletter
will be the character itself. You can then do:if letter == guess:
And to wrap it up, do list assignment by index. Someone already mentioned why not to use insert in this scenario, so I won’t repeat them. The following will instead overwrite the item at
display
indexi
with the guessed character:display[i] = guess
So - ChatGPT is great for breaking down concepts like this and answering questions about the basics until you get the hang of it. I would recommend crafting some programs while asking it for help on anything you get stuck with, until you can craft the programs without involving it (and still you can paste the programs into it and ask for pointers / fixes that it can see). I’m currently learning Go with assistance from ChatGPT and it’s hugely useful.
One other angle you could come at it from – this might venture into unpopularopinion territory, but I would actually recommend learning C at a very early stage. It’ll be tedious to make nontrivial programs with it, so you may not want to stick with it for your real projects, but since everything is bytes and pointers it gives you a chance to get extremely solid with the fundamentals before you start mucking around with slices / hashes / etc. I would recommend to try to get this particular problem working using C, which will be more work, but then when you come back and learn the Python concepts I think they’ll make a lot of sense and you’ll feel capable with them. IDK if it’ll work that way for you, but that’s what I did and I feel like it was a good way to go.
Best of luck + keep plugging
Yeah I’ve actually been using chatgpt as well as a few other resources! My biggest gripe is that chatgpt can’t really teach without showing. I want to understand where my logic was flawed, and be guided towards the correct answer, instead chatgpt will do a good job at explaining what I did wrong, and then showing me the correct code.
So c is a good starter language? Cuz I’m at the point now that I can just stackoverflow my way into making a smaller project, but I really want to learn how this all works and learn the fundamentals so I’m fluent