CODEWITHSUNDEEP
pythonlistrandom
Programmer
Programmer

Reputation: 314

Python: change random element from first column of 2D list

I have a list:

ls = [["a", "b"],
      ["c", "d"],
      ["e", "f"]]

I want to change a, c or e to 1. I tried this:

import random

for num, row in enumerate(ls):
    r = random.choice(num[0])
    r[0] = 1
print(ls)

But I only get:

r = random.choice(num[0])
TypeError: 'int' object is not subscriptable

How can I change a random element from the first column of 2D array?

Upvotes: 0

Views: 94

Answers (1)

Andrej Kesely
Andrej Kesely

Reputation: 195408

Chose random number from 0 to len(ls) - 1 and change the first element in the row:

import random

ls = [["a", "b"], ["c", "d"], ["e", "f"]]

random_row = random.randint(0, len(ls) - 1)
ls[random_row][0] = 1

print(ls)

Prints (for example):

[['a', 'b'], 
 [1, 'd'], 
 ['e', 'f']]

Upvotes: 4

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