How to access number of iterations while looping over a string — Python

Question

I am trying to remove the first and last characters in a given string in python.

I want the if statement to replace the letter with an empty string, as the last line is attempting. But i is a str and not an int, so I cant use it to find the index in the replace function. I need some way to access the number of iterations to the string, and not the string letter itself, is there a simple thing I'm missing here?

def without_end(str):
  first = str[0]
  last = str[-1]
  for i in str:
    if i == first or i == last:
      new_string = str.replace(str[i], "")
  return new_string

Please clarify: Do you want to remove the first and the last character everywhere in the string? That would be easy: `text.replace(text[0], '').replace(text[1], '')` (I used the name `text` for the variable because `str` overwrites the built-in function with the same name) — Matthias, Jul 20 '23 at 16:11
That is useful to know, I didn't know you can have multiple functions one after another like this. Thanks — Lxxj, Jul 21 '23 at 09:01

score 1 · Answer 1 · answered Jul 20 '23 at 14:03

1

In Python you can do the following.

x = "foof"
x = x[1:-1]

This will result in the string oo.

answered Jul 20 '23 at 14:03

jodá

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7
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Ömer Sezer · Answer 2 · 2023-07-21T09:22:31.207

In this implementation, input_str[1:-1] slices the string to exclude the first and last characters, effectively removing them from the original string.

Avoid using the name str as a variable, as it is a built-in Python type, and using it as a variable name may cause confusion and unexpected behavior. I renamed the parameter to input_str to avoid any conflicts.

Code:

def without_end(input_str):
    return input_str[1:-1]

# Test the function
result = without_end("Hello")
print(result)  # Output: "ell"

According to feedback, the below code is the correct one. I leave the above code to stay there for a different perspective.

Code:

def without_end(input_str):
    first = input_str[0]
    last = input_str[-1]
    new_string = "".join([char for char in input_str if char != first and char != last])
    return new_string

# Tests
print(without_end("hello"))   # Output: "ell"
print(without_end("python"))  # Output: "ytho"
print(without_end("code"))    # Output: "od"
print(without_end("hellocode")) # Output: "llocod"

I think you have misunderstood the question. As I understand it, all characters in the string that are equal to the first or last letter should be removed. Otherwise the broken attempt with `replace` in the original code wouldn't make any sense. — Matthias, Jul 20 '23 at 16:08
You are right @Matthias, I refactored it again in the post. I misunderstood while quick response. — Ömer Sezer, Jul 21 '23 at 09:23

How to access number of iterations while looping over a string — Python

2 Answers2