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https://issues.apache.org/jira/browse/GROOVY-10683?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17939455#comment-17939455
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ASF GitHub Bot commented on GROOVY-10683:
-----------------------------------------
daniellansun commented on PR #2169:
URL: https://github.com/apache/groovy/pull/2169#issuecomment-2764351669
How about `for (int index, var item : items)`?
For example:
```groovy
// ① traverse a list
List<String> names = Arrays.asList("Alice", "Bob", "Charlie");
for (int i, String name : names) {
System.out.println(i + ": " + name.toUpperCase());
}
// ② traverse a matrix
int[][] matrix = {{1,2}, {3,4}};
for (int row, int[] cols : matrix) {
for (int col, int val : cols) {
System.out.printf("[%d,%d]=%d\n", row, col, val);
}
}
```
> Consider enhancing for loop to provide access to loop index or iterator
> -----------------------------------------------------------------------
>
> Key: GROOVY-10683
> URL: https://issues.apache.org/jira/browse/GROOVY-10683
> Project: Groovy
> Issue Type: New Feature
> Components: parser-antlr4
> Reporter: Eric Milles
> Priority: Minor
>
> When iterating over an array or iterable, there is choice between traditional
> counting loop for index access, declaring/managing an external variable to
> leverage for-each loop, or switching to {{eachWithIndex}} which requires
> quite a bit more runtime investment.
> {code:groovy}
> for (int i = 0, n = array.length; i < n; i += 1) {
> def val = array[i]
> }
> int idx = 0; for (val in array) {
> idx += 1;
> }
> // idiomatic and takes care of all the management, but lacks STC support for
> primitive arrays and adds the cost of method invocation for each iteration
> array.eachWithIndex { val, idx ->
> }
> {code}
> Please consider the possibility of {{for}} loop enhancements of
> [Gosu|https://gosu-lang.github.io/docs.html], which provides a direct syntax
> for index or iterator:
> {code}
> for (val in array index idx) {
> println "$idx: $val"
> }
> for (value in iterable iterator iter) { // could be ListIterator for List
> types, which increases options
> iter.remove() // for example
> }
> {code}
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