I want output to be shown once in for loop

Question

I want Else statement to be shown once if it's wrong. Please see the code which I tried.

lists = ['apple','grape','pineapple','orange']

password = "xyz"
def pass1():
    for i in lists:
        if i == password:
            print("Accepted!", "Password : " + i)
            break
        else:
            print("Password not found! Try again")
pass1()

Output:

Password not found! Try again
Password not found! Try again
Password not found! Try again
Password not found! Try again

Process finished with exit code 0

None of the items in `lists` matches the password, so the code is working as expected. Have you tried `return`-ing inside the `else` block? — Gino Mempin, Mar 23 '20 at 23:42
Check out this answer: https://stackoverflow.com/questions/7571635/fastest-way-to-check-if-a-value-exists-in-a-list - you don't need to iterate over your list. You can use the `in` keyword to test all values against your password criteria at once. — Jon Mitten, Mar 23 '20 at 23:45

Marsilinou Zaky · Answer 1 · 2020-03-23T23:51:56.917

If I understand your question correctly, you can do that by removing the else, if the loop ends and you didn't find the password in the list then it doesn't exist.

lists = ['apple','grape','pineapple','orange']

password = "xyz"
def pass1():
    for i in lists:
        if i == password:
            print("Accepted!", "Password : " + i)
            return
    print("Password not found! Try again")
pass1()

Another and more pythonic way

def pass2():
    if password in lists:
        print(print("Accepted!", "Password : " + lists.index(password)))
    else:
        print("Password not found! Try again")
pass2()

I don't see why you're not passing the password as a parameter?

Maybe consider doing it as follow

def pass3(password, lists):
    if password in lists:
        print(print("Accepted!", "Password : " + lists.index(password)))
    else:
        print("Password not found! Try again")

lists = ['apple','grape','pineapple','orange']
password = "xyz"
pass3(password, lists)

dhentris · Answer 2 · 2020-03-23T23:54:14.583

0

Actually you don't need looping if you just only want to check if the value in the lists, just try this:

def pass1():
    if password in lists:
        print("Accepted!", "Password : " + password)
    else:    
        print("Password not found! Try again")

but if you still want to iterating the list you can use return like this:

def pass1():
    for i in lists:
        if i == password:
            return print("Accepted!", "Password : " + i)
    return print("Password not found! Try again")

because if you not use return the last code still be printed even the password is true.

edited Mar 23 '20 at 23:54

answered Mar 23 '20 at 23:48

dhentris

198
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2
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I tried with the correct password and it shows 2 output "Accepted!" and "Password not found! Try again". I want it to be either of them. – programyer Mar 24 '20 at 00:52
if you want to be either of them just remove the return. – dhentris Mar 24 '20 at 03:49

score 0 · Answer 3 · answered Mar 24 '20 at 02:30

0

Another way to do it by using else on for loop
else block is executed only when every item is exhausted:

lists = ['apple','grape','pineapple','orange']

password = "xyz"
def pass1():
    for i in lists:
        if i == password:
            print("Accepted!", "Password : " + i)
            break
    else:
        print("Password not found! Try again")
pass1()

answered Mar 24 '20 at 02:30

ywbaek

2,971
3
9
28

But "Password not found! Try again" prints till it does not matches with the correct answer. I want it to be one time. – programyer Mar 24 '20 at 02:53
Copy and paste my code and try yourself. It only prints one time. – ywbaek Mar 24 '20 at 03:14

I want output to be shown once in for loop

3 Answers3