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iOS Swift Basics (retired) Control Flow For-In Loop

boris said
boris said
3,607 Points
Posted by boris said
boris said
3,607 Points

when i try and do the loop it does this

//: Playground - noun: a place where people can play

import UIKit

var todo = ["Complete Laundry", "Take out bee nest", "Return Calls", "Get water", "Go to Bed"]

for useless in todo { println()

}

for number in 1...0 { println("(number) times 2 is (number*2)")

}

fatal error: Can't form Range with end < start Playground execution failed: Execution was interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0).

  • thread #1: tid = 0x46003, 0x000000010668352c libswiftCore.dylib`function signature specialization <Arg[0] = Exploded, Arg[1] = Exploded, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage (Swift.StaticString, Swift.StaticString, Swift.StaticString, Swift.UInt) -> () + 44, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
    • frame #0: 0x000000010668352c libswiftCore.dylibfunction signature specialization <Arg[0] = Exploded, Arg[1] = Exploded, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage (Swift.StaticString, Swift.StaticString, Swift.StaticString, Swift.UInt) -> () + 44 frame #1: 0x000000010f5c3889 $__lldb_expr126main + 2185 at For-in-Loop.playground:14 frame #2: 0x00000001047be710 For-in-Loop frame #3: 0x00000001047c25f1 For-in-Loopreabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_owned (@in ()) -> (@out ()) + 17 frame #4: 0x00000001047c11f1 For-in-Looppartial apply forwarder for reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_owned (@in ()) -> (@out ()) + 81 frame #5: 0x00000001047c2620 For-in-Loopreabstraction thunk helper from @callee_owned (@in ()) -> (@out ()) to @callee_owned () -> (@unowned ()) + 32 frame #6: 0x00000001047c2657 For-in-Loopreabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_unowned @objc_block () -> (@unowned ()) + 39 frame #7: 0x0000000104e0b41c CoreFoundation__CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12 frame #8: 0x0000000104e01165 CoreFoundationCFRunLoopDoBlocks + 341 frame #9: 0x0000000104e00923 CoreFoundation`CFRunLoopRun + 851 frame #10: 0x0000000104e00366 CoreFoundationCFRunLoopRunSpecific + 470 frame #11: 0x0000000104eae661 CoreFoundationCFRunLoopRun + 97 frame #12: 0x00000001047bedc2 For-in-Loopmain + 1714 frame #13: 0x0000000107a99145 libdyld.dylibstart + 1 frame #14: 0x0000000107a99145 libdyld.dylib`start + 1
boris said
boris said
3,607 Points
boris said
boris said
3,607 Points

for some reason i named the constant useless

1 Answer

Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Hello Boris :

I see what you are doing wrong here, I will point them out, and then give you the options to fix them. Please see the notes in green in the coding.

var todo = ["Complete Laundry", "Take out bee nest", "Return Calls", "Get water", "Go to Bed"]

for useless in todo { 
         println() // Give println something to print 
}

for number in 1...0 { // Your rage is from 1 to 0 here
println("(number) times 2 is (number*2)")  // String interpolation missing \ 
}

/* 
   If this was to work, it would print something like
   1 times 2 is 0
   1 times 2 is 0
   1 times 2 is 0

   This is why it does not work, your rage has to have a higher number.

*/

Here is how to fix that

var todo = ["Complete Laundry", "Take out bee nest", "Return Calls", "Get water", "Go to Bed"]

for useless in todo {
 println(useless)

}

for number in 1...10 { 
println("\(number) times 2 is \(number*2)")
}

Good luck.