Conditionally changing a value in an array

Question

Created Feb ’21

Replies 2

Boosts 0

Participants 2

I am unsure what I am doing wrong here. I want to limit the values in var training to 1.0. I have set up a test where the two printed values should be different, but the value is not changed even though a number higher than 1.0 is found.

Code Block struct Horse {
    var training : [Float]
}
var myHorses = [
    Horse(training: [1.5,0,0,0,0,0,0]),
    Horse(training: [0,0,0,0,0,0,0]),
    Horse(training: [0,0,0,0,0,0,0])
]
var horseIndex = 0
print(myHorses[horseIndex].training[0])
for var skills in myHorses[horseIndex].training {
    if skills > 1.0 {
        print("value > 1.0 found")
        skills = 1.0
    }
}
print(myHorses[horseIndex].training[0])

Answered by OOPer in 662842022

Even when you apply var to the control variable of for-in statement, the variable holds the copy of each element of the Array as its initial value.
You cannot change the original Array when you just modify the control variable.

You need to write index based access when you want to modify the Array:

Code Block for index in myHorses[horseIndex].training.indices {
    if myHorses[horseIndex].training[index] > 1.0 {
        print("value > 1.0 found")
        myHorses[horseIndex].training[index] = 1.0
    }
}

Boost

Answer 1

OOPer OP

Feb ’21

Accepted Answer

Even when you apply var to the control variable of for-in statement, the variable holds the copy of each element of the Array as its initial value.
You cannot change the original Array when you just modify the control variable.

You need to write index based access when you want to modify the Array:

Code Block for index in myHorses[horseIndex].training.indices {
    if myHorses[horseIndex].training[index] > 1.0 {
        print("value > 1.0 found")
        myHorses[horseIndex].training[index] = 1.0
    }
}

0

Answer 2

imey OP

Feb ’21

I knew there was a problem with my for loop, thanks for clearing that up :D

0