I'm looking for a way to stop iterating the just inner loop once a condition is met. I thought of using "continue" but it's not doing what i wanted.
"break" seems to break the entire loop including the outer loop.
So in my code, once the condition is met. I want to stop iterating j but i want to start iterating i again. Thank you,
for i in 0..<sortedArray.count{
for j in 1..<sortedArray.count{
if sortedArray[j] == sortedArray[i]{
//I want to skip iterating inner loop j from now. and back to iterating i
}
}
}
Break just breaks the inner loop.
e.g.
for var i in 0...2
{
for var j in 10...15
{
print("i = \(i) & j = \(j)")
if j == 12
{
break;
}
}
}
Output -->
i = 0 & j = 10
i = 0 & j = 11
i = 0 & j = 12
i = 1 & j = 10
i = 1 & j = 11
i = 1 & j = 12
i = 2 & j = 10
i = 2 & j = 11
i = 2 & j = 12
The nested index loop and subsequent element access by index approach (anArray[accessByThisIndex]) is kind of C++'ish rather than Swifty. Depending on you application, you can make good use of neat features in Swift to achieve your goal.
E.g., assuming (based on the anme of your array) your array is sorted,
let sortedArray = [2, 5, 7, 9]
for i in sortedArray {
for j in sortedArray where j <= i {
print(j)
}
print("-----")
}
/* 2
-----
2
5
-----
2
5
7
-----
2
5
7
9
----- */
Note that we don't care about the indices of the array above, instead accessing the elements of the array directly in the for ... in (... where ...) loop(s).
Another alternatively coulkd make use of prefixUpTo(:_)
for i in 1...sortedArray.count {
sortedArray.prefixUpTo(i).forEach {
print($0)
}
print("-----")
}
/* same printout as above */
Related
i just started learning dart but there is something i cant figure out.
the first loop it prints me from 1 3 5 7 9
the second one it prints for me from 0 to 9.
why did it remove the even numbers from the loop below? i only added a variable in the first loop
void main () {
for(double a = 0; a <10 ; a++)
{
double b = a++;
print (a);
}
print("---");
for(double a = 0; a <10 ; a++)
{
print(a);
}
}
the a++ is a shortcut to a = a +1, which means that b in each step is getting the value of a+1 and the second loop would only print odd numbers since you are jumping 2 steps in each loop (a++ in the loop brackets and the b = a++)
So I have arr = randi([0,20],20,1). I want to show: If there are numbers less than 5, fprintf('Yes\n') only once. Im using a for loop (for i = 1 : length(arr)) and indexing it.
As your description, maybe you need if statement within for loop like below
for i = 1:length(arr)
if arr(i) < 5
fprintf('Yes\n');
break
end
end
If you want to print Yes once, you can try
if any(arr < 5)
fprintf('Yes\n')
endif
If you don't want to use break, the code below might be an option
for i = 1:min(find(arr <5))
if (arr(i) < 5)
fprintf('Yes\n');
end
end
You can use a break statement upon finding the first value under 5 and printing the Yes statement.
Using a break Statement:
arr = randi([0,20],20,1);
for i = 1: length(arr)
if arr(i) < 5
fprintf("Yes\n");
break;
end
end
Extension:
By Using any() Function:
Alternatively, if you'd like to concise it down without the need for a for-loop the any() function can be used to determine if any values within the array meet a condition in this case arr < 5.
arr = randi([0,20],20,1);
if(any(arr < 5))
fprintf("Yes\n");
end
By Using a While Loop:
Check = 0;
arr = randi([0,20],20,1);
i = 1;
while (Check == 0 && i < length(arr))
if arr(i) < 5
fprintf("Yes\n");
Check = 1;
end
i = i + 1;
end
I have following line in my code:
for (i = 0, j = count - 1; i < count; j = i++)
Can anyone help to remove the two compiler warnings, that i++ will be removed in Swift 3.0 and C-style for statement is depreciated?
You could use this:
var j = count-1
for i in 0..<count {
defer { j = i } // This will keep the cycle "logic" all together, similarly to "j = i++"
// Cycle body
}
EDIT
As #t0rst noted, be careful using defer, since it will be executed no matter how its enclosing scope is exited, so it isn't a 100% replacement.
So while the standard for ( forInit ; forTest ; forNext ) { … } will not execute forNext in case of a break statement inside the cycle, a return or an exception, the defer will.
Read here for more
Alternatively, lets go crazy to avoid having to declare j as external to the loop scope!
Snippet 1
let count = 10
for (i, j) in [count-1..<count, 0..<count-1].flatten().enumerate() {
print(i, j)
}
/* 0 9
1 0
2 1
3 2
4 3
5 4
6 5
7 6
8 7
9 8 */
Snippet 2
for (i, j) in (-1..<count-1).map({ $0 < 0 ? count-1 : $0 }).enumerate() {
print(i, j)
}
Trying to win the prize for the craziest solution in this thread
Snippet 1
extension Int {
func j(count:Int) -> Int {
return (self + count - 1) % count
}
}
for i in 0..<count {
print(i, i.j(count))
}
Snippet 2
let count = 10
let iList = 0..<count
let jList = iList.map { ($0 + count - 1) % count }
zip(iList, jList).forEach { (i, j) in
print(i, j)
}
You could use a helper function to abstract away the wrapping of j as:
func go(count: Int, block: (Int, Int) -> ()) {
if count < 1 { return }
block(0, count - 1)
for i in 1 ..< count {
block(i, i - 1)
}
}
How to use two variables in for loop?
for j,k in zip(range(x,0,-1),range(y,-1,-1)
I want to implement this in Swift.
If your range is a python function, then the Swift-y solution will be:
let x = 100
let y = 99
let rx = reverse(0...x)
let ry = reverse(-1...y)
for (j,k) in zip(rx, ry) {
println(j, k)
}
if you're looping over a dictionary you can loop like this
for (key,value) in dictionary {
}
if an array etc. you're going to have to use a c style for loop
just sub in whatever start and end indices you need
for var j = 0 , k = 0; j < 10 && k < 10; j++ , k++ {
}
EDIT
missed the zip in there. You can loop like this
for (j,k) in zip(range1, range2) {
}
Suppose:
1 A
2 B
3 C
I need to print the value corresponding to 1-> A. I have put each in an array:
d1[1,2,3] and s1[A,B,C]. Now I need to print the value in the form shown in the above:
d1[0] s1[0]
1 A
How can I do this using UnityScript? In the program, I did id printing in this format:
1 A
1 B
1 C
2 A
2 B
2 C
What you have probably done, and I'm guessing without seeing the code is something along that you have a for loop within a for loop which means you're processing the first item in the first array and then all items in the second:
for (var i = 0; i < d1.Length; i++) {
for(var j = 0; j < s1.length; j++ {
Debug.log(d1[i] + " " + s1[j])
}
}
Your options depend on the array sizes and how you want to handle them. For example if you know they're the same size consistently then
for(var i = 0; i < d1.Length; i++) {
Debug.log(d1[i] + " " + s1[i])
}
should work. I would wonder if what you're trying to achieve could be done with a different data structure such as a dictionary, etc.