Iterating Through NSIndexSet

Question

If you have an NSArray object named anArray and an NSIndexSet object named anIndexSet, you can iterate forward through an index set as shown in below.

Excerpt, Apple Documents:

package test;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

public class WriteFile {

int lineNumber = 1;

protected void byLine(List<String> lines) throws IOException {
    // neue Datei erstellen
    PrintWriter writer = new PrintWriter("C:\\...\\test2.txt", "UTF-8");
    // für jeden String (eingelesene Zeile) in der Arraylist
    for( String line: lines) {
        // Counter für die Zeilennummern
            writer.println("*/ " + lineNumber + " /*" + " " + line);
            lineNumber++;
        }
    // Writer schließen
    writer.close(); 
    }

}

Why terminating NSRangeException in the above scenario?

Answer 1

我认为这个例子更好地描述了这种情况。另外，没有像你说的那样使用空数组。非常感谢rmaddy !!!

NSMutableArray *mutableArray = [NSMutableArray arrayWithObjects:@"K",@"G",@"G",@"E",@"R",@"G",@"E",@"G",@"G",@"M", nil];

NSIndexSet *anIndexSet = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, [mutableArray count])];

NSUInteger index = [anIndexSet lastIndex];

while (index != NSNotFound) {
    if ([[mutableArray objectAtIndex:index] isEqualToString:@"G"]) {
        [mutableArray removeObjectAtIndex:index];
    }
    index = [anIndexSet indexLessThanIndex:index];
}
NSLog(@" %@", mutableArray);