Locating values in a python array and assigning specific values

Question

I have the following vector:

posicao = [47, 62, 24, 18, 47, 62, 63, 78, 68, 87, 24, 18, 68, 87, 63, 78]

I need to search in this vector the values [24, 18].

After locating them all, I need to assign a random but EQUAL value to these positions.

I’m trying so many ways, but I can’t.

Could someone help me?

Grateful to those who can.

Answer 1

For this case the random value is generated at the beginning and only once, which will then be applied in all substitutions. These can be done based on a list of values to be replaced, and running through the two, with a double for:

import random

posicao = [47, 62, 24, 18, 47, 62, 63, 78, 68, 87, 24, 18, 68, 87, 63, 78]
aleatorio = random.randrange(0,200)

for j in range(len(posicao)): #percorrer a lista original
    if posicao[j] in [24,18]: #ver se o elemento se encontra nos que se quer trocar
        posicao[j] = aleatorio #fazer a troca

Another solution is to use the method index array to find the element. And although it is simpler to throw an exception if the element does not exist, in this case it would be if the element that wants to place the random does not exist in the array posicao.

Controlling already these exceptions would be this way:

import random

posicao = [47, 62, 24, 18, 47, 62, 63, 78, 68, 87, 24, 18, 68, 87, 63, 78]
aleatorio = random.randrange(0,200)

for i in [24,18]: #valores a colocar o mesmo aleatório
    try:
        posicao[posicao.index(i)] = aleatorio
    except:
        pass

Edit

For a search and replacement by indexes can do:

import random

posicao = [47, 62, 24, 18, 47, 62, 63, 78, 68, 87, 24, 18, 68, 87, 63, 78]
aleatorio = random.randrange(0,200)

for i in [2, 3, 10, 11]: #indices a substituir aqui no for
    posicao[i] = aleatorio