Get Excel columns in list (Python or Javascript)

Question

I am trying to get a list/array of the columns of an Excel spreadsheet, from A until ZZ.

["A","B","C", ... , "ZX","ZY","ZZ"]

What I have tried so far:

(Javascript)

const alphabetList = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split('');
const alphabetListCopy = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split('');

for (var i=0; i < alphabetListCopy.length; i++){
  for (var j=0; i < alphabetListCopy.length; j++){
    alphabetList.push(alphabetList[i][j]);
  }
}

console.log(alphabetList);

and this returns Error: Invalid array length

(I did the loop with alphabetListCopy to avoid this error https://forum.freecodecamp.org/t/push-new-element-into-array-using-for-loop/225401#:~:text=Your%20code%20crashed,push%20an%20element.)

In python I tried:

alphabet = "A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z".split("-")

for letter in alphabet:
    for a in alphabet:
        alphabet.append(letter + a)
        
print(alphabet)

and this returns a MemoryError (I assumed it created an infinite loop)

Asked By: Francisco Barroca

||

Source

Answer 1

Code:

import string
alphabet = list(string.ascii_uppercase)

new= []
for alpha in alphabet:
    for a in range(len(alphabet)):
        new.append(alpha+alphabet[a])
    
len(alphabet+new)

The same code in single line (ternary format):

alphabet+[alphabet[a]+alpha for a in range(len(alphabet)) for alpha in alphabet]

New list length 702

Answered By: Stackpy

Answer 2

For an easy approach to get the alphabet:

alphabet = [chr(i) for i in range(65, 91)]

To get all combinations, itertools has a nice collection of tools:

import itertools
alpha_combi = [''.join(subset) for subset in itertools.product(alphabet, repeat=2)]
alphabet += alpha_combi

where each subset is a tuple of two letters.

Answered By: Flow

Answer 3

The code you are providing is making an infinite loop because you are appending values to an array and you are trying to add a value to a 2-dimension array while alphabetList is a 1-dimansion.

If you want to have a list of the values from A to ZZ in Javascript you can do this instead :

const alphabetList = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split('');

// here we do not want to make it const since we are populating it
let alphabetListCopy = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split('');
for(i = 0; i < alphabetList.length; i++) {
    for(j = 0; j < alphabetList.length; j++) {
        alphabetListCopy.push(`${alphabetList[i]}${alphabetList[j]}`) // we add to the array the new value
    }
}

Answered By: Aesahaettr

Get Excel columns in list (Python or Javascript)

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