objc写一个NSMutableArray不连续索引替换对象的方法

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NSMutableArray内置的方法-(void)replaceObjectsAtIndexes:(NSIndexSet*)set withObjects:(NSArray*)objs
只能替换一段连续索引内的对象，比如2 to 10之间的对象，如果我想要替换1,3,5索引位置的对象需要自己写代码。
在ruby中对于数组对象有一个values_at方法可以取得不连续索引的对象：

2.2.1 :048 > ary = %w[a b c d e f g] => ["a", "b", "c", "d", "e", "f", "g"] 2.2.1 :049 > ary.values_at(*[1,3,5]) => ["b", "d", "f"]

如果是替换不连续索引的对象，稍微麻烦点：

2.2.1 :053 > idxes => [1, 3, 5] 2.2.1 :054 > objs => ["X", "X", "X"] 2.2.1 :055 > idxes.zip(objs) => [[1, "X"], [3, "X"], [5, "X"]] 2.2.1 :056 > idxes.zip(objs).each {|i,v|ary[i] = v} => [[1, "X"], [3, "X"], [5, "X"]] 2.2.1 :057 > ary => ["a", "X", "c", "X", "e", "X", "g"]

如果idxes数量小于objs则忽略多余的对象，反之如果idxes数量大于objs则用nil补足：

2.2.1 :062 > objs = %w[X X X] => ["X", "X", "X"] 2.2.1 :063 > idxes = [1,6] => [1, 6] 2.2.1 :064 > idxes.zip(objs).each {|i,v|ary[i] = v} => [[1, "X"], [6, "X"]] 2.2.1 :065 > ary => ["a", "X", "c", nil, "e", nil, "X"] 2.2.1 :059 > objs = [] => [] 2.2.1 :060 > idxes.zip(objs).each {|i,v|ary[i] = v} => [[1, nil], [3, nil], [5, nil]] 2.2.1 :061 > ary => ["a", nil, "c", nil, "e", nil, "g"]

下面写一个objc中类似的实现:

#import <Foundation/Foundation.h>@interface NSMutableArray (HyRandReplace)@end@implementation NSMutableArray (HyRandReplace)-(void)replaceObjectsAtIndexesRand:(NSArray*)idxes withObjects:(NSArray*)objs{    NSUInteger count_idxes = [idxes count];    //NSUInteger count_objs = [objs count];    for(NSUInteger i = 0;i < count_idxes;i++){        NSUInteger x = [idxes[i] intValue];        @try{            [self replaceObjectAtIndex:x withObject:objs[i]];        }        @catch(NSException *e){            NSLog(@"%@:%@",e.name,e.reason);            [self replaceObjectAtIndex:x withObject:[NSNull null]];        }    }}@endint main(void){    @autoreleasepool{        NSArray *idxes = @[@1,@3,@5];        //NSArray *objs = @[@"LOVE",@"FOR"];        NSArray *objs =@[];        NSMutableArray *mary = [@[@"a",@"and",@"b",@"for",@"ever",@"..."]             mutableCopy];        NSLog(@"%@",mary);        [mary replaceObjectsAtIndexesRand:idxes withObjects:objs];        NSLog(@"%@",mary);    }    return 0;}

当然ruby里也可以做类似的操作，why not？ruby比objc还要动态：

2.2.1 :066 > class Array2.2.1 :067?>   def replace_rand(idxes,objs)2.2.1 :068?>     idxes.zip(objs).each {|i,v|self[i] = v}2.2.1 :069?>     end2.2.1 :070?>   end => :replace_rand 2.2.1 :073 > ary => ["a", "b", "c", "d", "e", "f", "g"] ary.replace_rand          2.2.1 :074 > ary.replace_rand(idxes,objs) => [[1, "X"], [6, "X"]] 2.2.1 :075 > ary => ["a", "X", "c", "d", "e", "f", "X"]

see！ruby扩展类要比objc简单的多，所以看swift的了 :)

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