Why doesn't my if...in statement work in python?

kei 0
Viewed 65

this program takes 3 lists of numbers, and compares A and B to the list n. if a term from A is in n, the happiness increases. if a term from B is in n, the happiness decreases. However, when I am doing these calculations, the if ... in statement to check if a term from A/B is in n doesn't work - I have done print(happy) after each one to check, and I get no result

A = []
B = []
n = []
happy = 0
lengthn, lengthAB = input("").split()
for i in lengthn:
    numbers = input("")
newNumbers = numbers.split()
n.append(newNumbers)
for i in lengthAB:
    numbers = input("")
ANumbers = numbers.split()
A.append(ANumbers)
for i in lengthAB:
    numbers = input("")
BNumbers = numbers.split()
B.append(BNumbers)

long = int(lengthAB)
for i in range(long):
    j = int(i)
    if A[j - 1] in n:
        happy = happy + 1
        print(happy)
    if B[j - 1] in n:
        happy = happy - 1
        print(happy)
    i = i + 1

print(happy)

Thank you so much for the help!!

arrays python
4 Answers

You appended a list to n, not each element of that list. You can write

n.extend(newNumbers)

instead.

You could just write n = newNumbers.split(), but as pointed out in a comment, you probably have an indentation error:

for i in lengthn:
    numbers = input("")
    newNumbers = numbers.split()
    n.extend(newNumbers)

Or, you don't need split at all:

for i in lengthn:
    number = int(input(""))
    n.append(number)

At some point, you probably mean to convert the string inputs to integers; may as well do that immediately after reading the string. (I'm declaring various techniques for handling conversion errors beyond the scope of this answer.)

chepner0

Contrary to what you seem to expect the variables: lengthn, lengthAB are strings

The for-loop

for i in lengthn:
    numbers = input("")

iterates over the characters in the string lengthn. If lengthn='12' it will ask to provide input twice.

If lengthAB is '13' for example you will get 2 numbers in your list BNumbers but later on you try to test 13 values because int('13') is 13.

Ronald van Elburg0 
 for i in lengthn:
     numbers = input("")

so the numbers you are getting are the form of string it's will iterate on string rather then a number.

Ahmed Arshed0

You should look for beeter python book. Based on desription I think this should look like this:

def happiness(A, B, n):
    return sum(x in n for x in A) - sum(x in n for x in B)

def get_data(prompt=""):
    return [int(x) for x in input(prompt).split()]

print(happiness(get_data(), get_data(), get_data()))

https://ideone.com/Q2MZCo

Marek R0
Related