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+---- Thread: [Python] Reverse array challenge code I wrote (/showthread.php?tid=6122992)
Reverse array challenge code I wrote - Doc - Nov 23, 2020
Posting this here looking for constructive criticism. If anyone's got any tips/advice on things I could've done better/differently, please feel free to say so.
The code challenge was:
- Prompt: Reverse an array. A classic code interview question.
- Difficulty: easy
- Languages: no-restrictions
- Constraints: The function should take in any array and return that array in reverse. If your language has a native .reverse() function cannot use it because this is a test of complexity and not how well you can use a function!
- Bonus: Do this without allocating any extra memory. This is called modifying the array "in-place"!
Code
# reverse an array challenge
# gotta have numpy
import numpy as np
# big daddy string to get things done
def string_to_array_to_reversed_array():
# for handling user input
def user_input_function(user_input): # user_input to take in the input when called
user_input = list(user_input.replace(" ", "")) # user_input is reassigned it's input string as a list, while user_input.replace trims any white space out
return np.array(user_input, order = 'C') # return user_input list as an array in contiguous order to array_arg parameter in reverse_array function
# for reversing the array
def reverse_array(array_arg): # array_arg takes in the return from user_input_function
return np.flipud(array_arg) # FLIPS THE ARRAY, DOESN'T REVERSE IT. YOU SEE THE .flipud part right?. NOTHING WAS SAID ABOUT FLIPPING. ONLY REVERSING.
# x assigned to take in final return value and store it for printing
x = reverse_array(user_input_function(input("Please type in a single word as a string: "))) # get user input
return x # RESULTS ARE IN!
# call "main" function and make shit happen, store in reversed_array for printing.
reversed_array = string_to_array_to_reversed_array()
print(reversed_array)I dunno if I got the bonus, although I DID get a lotta much needed experience using numpy for certain things, so at least there's that.
Anyway lemme know what you guys think.
RE: Reverse array challenge code I wrote - Qismon - Dec 1, 2020
Code
def reverse_array(normalArray):
reversedArray = normalArray[::-1]
return reversedArray
normalArray = [1, 2, 3, 4, 5]
reversedArray = reverse_array(normalArray)
print(reversedArray)RE: Reverse array challenge code I wrote - vorticalbox - Dec 1, 2020
(Dec 1, 2020 09:07 AM)Qismon Wrote:Codedef reverse_array(normalArray):
reversedArray = normalArray[::-1]
return reversedArray
normalArray = [1, 2, 3, 4, 5]
reversedArray = reverse_array(normalArray)
print(reversedArray)
I would say using pythons list fucntiosm would fall under pythons built in reverse.
RE: Reverse array challenge code I wrote - SecuroServ - Dec 1, 2020
I think what they are looking for is, loop over the array, switch first item with last item, second item with second last item etc until you reach the middle.
I know using a library isn't in their constraints, but I'm pretty sure they also mean that your thing isn't allowed because they are looking for complexity like they said
RE: Reverse array challenge code I wrote - vorticalbox - Dec 1, 2020
(Dec 1, 2020 09:27 AM)SecuroServ Wrote: I think what they are looking for is, loop over the array, switch first item with last item, second item with second last item etc until you reach the middle.
I know using a library isn't in their constraints, but I'm pretty sure they also mean that your thing isn't allowed because they are looking for complexity like they said
Completely agree. No packages allowed.
He is my solution
PHP Code
<?php
def reverse(lst):
length = len(lst)
tmp = [0 for I in range(length)]
for i in range(length):
idx = (length - 1) - i
tmp[i] = lst[idx]
return tmp
RE: Reverse array challenge code I wrote - L E G I Ø N - Dec 2, 2020
This is the easiest solution I could think of. Just looping through the original array backwards and adding all the items to a new array.
PHP Code
<?php
def reverse(arr):
rev = []
for x in range(len(arr), 0, -1):
rev.append(x)
return rev
RE: Reverse array challenge code I wrote - vorticalbox - Dec 2, 2020
(Dec 2, 2020 07:14 AM)L E G I Ø N Wrote: This is the easiest solution I could think of. Just looping through the original array backwards and adding all the items to a new array.
Should it not be this?
PHP Code
<?php
def reverse(arr):
rev = []
for x in range(len(arr), 0, -1):
rev.append(arr[x])
return rev
RE: Reverse array challenge code I wrote - Doc - Dec 8, 2020
Honestly it was kinda confusing for me to figure out how to go about doing this, primarily because Python doesn't technically have arrays, it has this weird kind of "lists" (I actually saw a pretty good meme about that recently) that can be a bit confusing to work with. Trying to reverse an array "in-place" (which was what I was originally wanting to do) is something I'd think is easier and more straightforward when using languages that have "normal" arrays.
RE: Reverse array challenge code I wrote - synchronizing - Dec 9, 2020
This will reverse even and odd lists with almost zero memory space used, and quicker than most other solutions since it only iterates to half of the length of the list (though same big O).
PHP Code
<?php
def rev(lst):
for i in range(len(lst) // 2):
lst[i], lst[len(lst) - i - 1] = lst[len(lst) - i - 1], lst[i]
return lst
print(rev([1, 2, 3, 4, 5, 6, 7])) # [7, 6, 5, 4, 3, 2, 1]
print(rev([1, 2, 3, 4, 5, 6, 7, 8])) # [8, 7, 6, 5, 4, 3, 2, 1]