How to make a condition if the value isn't exist then some sequential actions take place, and if the value isn't exist then other actions take place

Question

I want to make a condition if the value isn't exist then some sequential actions take place, and if the value isn't exist then other actions take place

def func():
    first_array = [1, 3, 5, 7, 9]
    second_array = [2, 4, 6, 8, 10]
    found = False

    for i in range(len(first_array)):
        if first_array[i] == second_array[i]:
            found = True
            indeks_found = i
        if found == True:
            break

Local variable indeks_found doesn't exist (or indeks_found doesn't have any value). [I don't know]

In other case, if we change the array to be like this:

first_array = [1, 3, 5, 7, 9]
second_array = [2, 4, 5, 11, 13]

Then, indeks_found is exist (or indeks_found does have a value) [I don't know]

if indeks_found have any value, then do this sequential actions (we call it A) else if indeks_found doesn't have any value, then do this sequential actions (we call it B)

if indeks_found exist, then:
    do A
else: indeks_found doesn't exist, then:
    do B

So, how to make source code of this in python?

Answer 1

def func():
    first_array = [1, 3, 5, 7, 9]
    second_array = [2, 4, 6, 8, 10]
    found = False
    indeks_found = None # initialize to none

    for i in range(len(first_array)):
        if first_array[i] == second_array[i]:
            found = True
            indeks_found = i
        if found == True:
            break
    if indeks_found == None:
        # indeks_found was not changed, i.e nothing found
        print('do A')
    else:
        print('do B')

Also you could simplify the for loop body to:

        if first_array[i] == second_array[i]:
            found = True
            indeks_found = i
            break

---

If you really want to test if a variable has been defined, you can do so by:

try:
    indeks_found
except:
    # indeks_found was not defined
else:
    # indeks_found has a value