我怎么能转换一个NSArray到NSDictionary ，通过阵列的对象的一个int领域作为重点NSDictionary ？
Answer 1:
- (NSDictionary *) indexKeyedDictionaryFromArray:(NSArray *)array
{
id objectInstance;
NSUInteger indexKey = 0U;
NSMutableDictionary *mutableDictionary = [[NSMutableDictionary alloc] init];
for (objectInstance in array)
[mutableDictionary setObject:objectInstance forKey:[NSNumber numberWithUnsignedInt:indexKey++]];
return (NSDictionary *)[mutableDictionary autorelease];
}
Answer 2:
试试这个法宝：
NSDictionary *dict = [NSDictionary dictionaryWithObjects:records
forKeys:[records valueForKey:@"intField"]];
仅供参考，这是可能的，因为这种内置功能：
@interface NSArray(NSKeyValueCoding)
/* Return an array containing the results of invoking -valueForKey:
on each of the receiver's elements. The returned array will contain
NSNull elements for each instance of -valueForKey: returning nil.
*/
- (id)valueForKey:(NSString *)key;
Answer 3:
这增加了一个类别扩展NSArray 。 需要C99模式（这是默认的这些天，但以防万一）。
在.h某个文件，可以将#import所有编..
@interface NSArray (indexKeyedDictionaryExtension)
- (NSDictionary *)indexKeyedDictionary
@end
在.m文件..
@implementation NSArray (indexKeyedDictionaryExtension)
- (NSDictionary *)indexKeyedDictionary
{
NSUInteger arrayCount = [self count];
id arrayObjects[arrayCount], objectKeys[arrayCount];
[self getObjects:arrayObjects range:NSMakeRange(0UL, arrayCount)];
for(NSUInteger index = 0UL; index < arrayCount; index++) { objectKeys[index] = [NSNumber numberWithUnsignedInteger:index]; }
return([NSDictionary dictionaryWithObjects:arrayObjects forKeys:objectKeys count:arrayCount]);
}
@end
使用示例：
NSArray *array = [NSArray arrayWithObjects:@"zero", @"one", @"two", NULL];
NSDictionary *dictionary = [array indexKeyedDictionary];
NSLog(@"dictionary: %@", dictionary);
输出：
2009-09-12 08:41:53.128 test[66757:903] dictionary: {
0 = zero;
1 = one;
2 = two;
}
Answer 4:
这是一个创建的一个例子NSMutableDictionary从员工列表NSMutableArray ：
NSMutableArray *emloyees = [[NSMutableArray alloc]initWithObjects:@"saman",@"Ruchira",@"Rukshan",@"ishan",@"Harsha",@"Ghihan",@"Lakmali",@"Dasuni", nil];
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
for (NSString *word in emloyees) {
NSString *firstLetter = [[word substringToIndex:1] uppercaseString];
letterList = [dict objectForKey:firstLetter];
if (!letterList) {
letterList = [NSMutableArray array];
[dict setObject:letterList forKey:firstLetter];
}
[letterList addObject:word];} NSLog(@"dic %@",dict);
Answer 5:
- (NSDictionary *) indexKeyedDictionaryFromArray:(NSArray *)array
{
NSMutableDictionary *mutableDictionary = [[NSMutableDictionary alloc] init];
[array enumerateObjectsUsingBlock:
^(id obj, NSUInteger idx, BOOL *stop){
NSNumber *index = [NSNumber numberWithInteger:idx];
[mutableDictionary setObject:obj forKey:index];
}];
NSDictionary *result = [NSDictionary.alloc initWithDictionary:mutableDictionary];
return result;
}
Answer 6:
我创建了一个简单的库，称为LINQ到的ObjectiveC ，这是方法的集合，使得这类问题很容易解决。 在你的情况，你需要的LINQ到的ObjectiveC toDictionary方法，其中通过按键选择指定你的“廉政”字段：
NSDictionary* dictionary = [sourceArray toDictionaryWithKeySelector:^id(id item) {
return [item intField];
}];
这将返回其中的键由给定字典intField源阵列英寸
文章来源: Convert NSArray to NSDictionary
