Re: foreach with assoc. array
On Wednesday, 1 March 2023 at 19:05:10 UTC, DLearner wrote:
```
Error: variable `wk_Idx` is shadowing variable
`for3.main.wk_Idx`
```
Why is this usage wrong?
Or use the `each` template which is almost the same as `foreach`
to avoid the shadowing variable issue.
```d
import std.algorithm, std.range, std.stdio;
enum len = 10;
void main()
{
int[len] IntArr, i, n;
len.iota.each!((i, n) => IntArr[i] = n);
IntArr.writeln; // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
assert(IntArr == len.iota.array);
}
```
SDB@79
Re: foreach with assoc. array
On Wednesday, 1 March 2023 at 19:05:10 UTC, DLearner wrote: (1) & (2) compile and run with the expected results. But (3) fails with: ``` Error: variable `wk_Idx` is shadowing variable `for3.main.wk_Idx` ``` Why is this usage wrong? With `foreach`, you can't reuse an existing variable as the loop variable. It always declares a new one. If you want to reuse an existing variable for your loop, you have to use `for`.
foreach with assoc. array
Hi
Please consider (1):
```
void main() {
import std.stdio;
int wk_Idx;
int[2] IntArr;
IntArr[0] = 1;
IntArr[1] = 2;
for (wk_Idx = 0; wk_Idx <= 1; wk_Idx = wk_Idx + 1) {
writeln("wk_Idx = ", wk_Idx, " IntArr = ", IntArr[wk_Idx]);
}
}
```
Now consider (2), which is (1) via assoc. array:
```
void main() {
import std.stdio;
int wk_Idx;
int[int] IntArr;
IntArr[0] = 1;
IntArr[1] = 2;
for (wk_Idx = 0; wk_Idx <= 1; wk_Idx = wk_Idx + 1) {
writeln("wk_Idx = ", wk_Idx, " IntArr = ", IntArr[wk_Idx]);
}
}
```
And finally (3) which is (2) via a foreach:
```
void main() {
import std.stdio;
int wk_Idx;
int[int] IntArr;
IntArr[0] = 1;
IntArr[1] = 2;
foreach (wk_Idx; IntArr.keys) {
writeln("wk_Idx = ", wk_Idx, " IntArr = ", IntArr[wk_Idx]);
}
}
```
(1) & (2) compile and run with the expected results.
But (3) fails with:
```
Error: variable `wk_Idx` is shadowing variable `for3.main.wk_Idx`
```
Why is this usage wrong?
