Use of unresolved Identifier when using for loop in Swift

Question

I am new to programming with swift and am confused as to why the program does not recognise what I have labeled as "test", claiming it is unresolved.

import UIKit

var rainfall = [38,94,142,149,236,305,202,82,139,222,178,103]
var raindays = [3,6,8,7,12,16,10,8,12,14,11,7]
let crit_raindays = 11
let et_raindays_lessthan_11 = 150
let et_raindays_morethan_11 = 120
let max_h2Ostore = 150
var evap_transpiration: [Int] = []


for i in raindays {
    if i <= 11 {
        var test = et_raindays_lessthan_11
    }
    else if i > 11 {
        var test = et_raindays_morethan_11
    }
    evap_transpiration.append(test)
}

The variable test does not seem to be assigned properly, I have no idea why. Error message: Use of unresolved identifier "test"

either declare test above the if or directly append inside the if clause — longbow
– longbow, Commented Jul 23, 2015 at 21:39
Appending inside the if statement seems possible, but declaring "test" outside the if statement is trivial because the whole point is that the value of "test" is different depending on which condition is met, would you know how to best solve this problem? — Jack Hayton
– Jack Hayton, Commented Jul 23, 2015 at 21:43
you can declare test outside the if block and then assign it in the if block — Will M.
– Will M., Commented Jul 23, 2015 at 21:46

Reynaldo Aguilar · Accepted Answer · 2015-07-23 21:46:33Z

2

When you declare a local variable in Swift, it will be accessible only after its declaration and in the the same scope. In your sample code: the first declaration will be accessible only inside the first if statement, and the second declaration will be accessible only inside the second one. The correct way is:

for i in raindays {
    var test = 0
    if i <= 11 {
       test = et_raindays_lessthan_11
    }
    else if i > 11 {
       test = et_raindays_morethan_11
    }

    evap_transpiration.append(test)
}

Even more, you don't need the second if, since if the first one is false, the second one will be always true. So, the code is:

for i in raindays {
    var test = 0
    if i <= 11 {
       test = et_raindays_lessthan_11
    }
    else {
       test = et_raindays_morethan_11
    }

    evap_transpiration.append(test)
}

answered Jul 23, 2015 at 21:46

Reynaldo Aguilar

1,9361 gold badge15 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Renzo · Accepted Answer · 2015-07-23 21:42:29Z

0

Try this:

var test: Int

for i in raindays {
  if i <= 11 {
    test = et_raindays_lessthan_11
  }
  else if i > 11 {
    test = et_raindays_morethan_11
  }
  evap_transpiration.append(test)
}

The reason is that you define test inside a block, so the scope is only internal to that block.

answered Jul 23, 2015 at 21:42

Renzo

27.6k5 gold badges54 silver badges64 bronze badges

1 Comment

Jack Hayton Over a year ago

Thank you so much, this has solved my problem, I will accept the answer once possible.

Shawjak3 · Accepted Answer · 2015-07-23 21:45:46Z

0

You need to declare test outside the for loop. Here is what I have that works.

import UIKit

var rainfall = [38,94,142,149,236,305,202,82,139,222,178,103]
var raindays = [3,6,8,7,12,16,10,8,12,14,11,7]
let crit_raindays = 11
let et_raindays_lessthan_11 = 150
let et_raindays_morethan_11 = 120
let max_h2Ostore = 150
var evap_transpiration: [Int] = []
var test = 0

for i in raindays {
if i <= 11 {
    test = et_raindays_lessthan_11
}
else if i > 11 {
    test = et_raindays_morethan_11
}
evap_transpiration.append(test)
}

answered Jul 23, 2015 at 21:45

Shawjak3

5411 gold badge5 silver badges19 bronze badges

Collectives™ on Stack Overflow

Use of unresolved Identifier when using for loop in Swift

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related