一、数组遍历：
1.常用for
NSMutableArray *testArray = [NSMutableArray array];
for (int i = 0; i < 100000; i++){
[testArray addObject:@(i)];
}
__block int sum = 0;
double date_for = CFAbsoluteTimeGetCurrent();
for (int i = 0; i < testArray.count; i++){
NSNumber *number = testArray[i];
sum = [number intValue] + sum;
}
double date_forEnd = CFAbsoluteTimeGetCurrent();
double date_forUse = date_forEnd - date_for;
NSLog(@"sum = %d forUseTime = %lf",sum,date_forUse);
结论for的计算时间为
2017-11-11 13:29:03.507891+0800 checkAllThing[4443:89434] sum = 704982704 forUseTime = 0.003164
2.使用for in进行遍历计算
sum = 0;
for (NSNumber *num in testArray){
int number = [num intValue];
sum += number;
}
double date_forInEnd = CFAbsoluteTimeGetCurrent();
double date_forInUse = date_forInEnd - date_forEnd;
NSLog(@"sum = %d ForInTimeUse = %f",sum,date_forInUse);
for in进行遍历的结果为
2017-11-11 13:29:03.510339+0800 checkAllThing[4443:89434] sum = 704982704 ForInTimeUse = 0.002497
3.使用enumerateObjectsUsingBlock进行计算
sum = 0;
[testArray enumerateObjectsUsingBlock:^(NSNumber * obj, NSUInteger idx, BOOL * _Nonnull stop) {
sum += [obj intValue];
}];
double dateEnumerateObjectNoOptionEnd = CFAbsoluteTimeGetCurrent();
double dateEnumerateObjectNoOptionUse = dateEnumerateObjectNoOptionEnd - date_forInEnd;
NSLog(@"sum = %d EnumerateObjectNoOption = %f",sum,dateEnumerateObjectNoOptionUse);
计算结果为
2017-11-11 13:29:03.515483+0800 checkAllThing[4443:89434] sum = 704982704 EnumerateObjectNoOption = 0.005145
4.enumerateObjectsWithOptions的计算
sum = 0;
[testArray enumerateObjectsWithOptions:NSEnumerationConcurrent usingBlock:^(NSNumber * obj, NSUInteger idx, BOOL * _Nonnull stop) {
sum += [obj intValue];
}];
double dateEnumerateOption = CFAbsoluteTimeGetCurrent();
double dateEnumerateOptionUse = dateEnumerateOption - dateEnumerateObjectNoOptionEnd;
NSLog(@"sum = %d EnumerateObjectNoOptionEnd = %f",sum,dateEnumerateOptionUse);
计算结果为
2017-11-11 13:29:03.520126+0800 checkAllThing[4443:89434] sum = -1728666209 EnumerateObjectNoOptionEnd = 0.004646
5.使用RAC流进行遍历
sum = 0;
NSArray *arrayData = [[testArray.rac_sequence map:^id(NSNumber * value) {
sum += [value intValue];
return value;
}]array];
double dateRac_sequence = CFAbsoluteTimeGetCurrent();
double dateRac_sequenceUse = dateRac_sequence - dateEnumerateOption;
NSLog(@"sum = %d rac_sequence = %f",sum,dateRac_sequenceUse);
计算结果为:
2017-11-11 13:29:03.708944+0800 checkAllThing[4443:89434] sum = 704982704 rac_sequence = 0.188814
结论分析
2017-11-11 13:29:03.507891+0800 checkAllThing[4443:89434] sum = 704982704 forUseTime = 0.003164
2017-11-11 13:29:03.510339+0800 checkAllThing[4443:89434] sum = 704982704 ForInTimeUse = 0.002497
2017-11-11 13:29:03.515483+0800 checkAllThing[4443:89434] sum = 704982704 EnumerateObjectNoOption = 0.005145
2017-11-11 13:29:03.520126+0800 checkAllThing[4443:89434] sum = -1728666209 EnumerateObjectNoOptionEnd = 0.004646
2017-11-11 13:29:03.708944+0800 checkAllThing[4443:89434] sum = 704982704 rac_sequence = 0.188814
通过结果分析得出以下结论
1.for in 的效率最高，但是在遍历过程中不能实时取得value所对应的index值
2.如果要通过value查询index可以使用enumerateObjectsWithOptions，使用此方法遍历可以使用多线程遍历。但是遍历过程可以无序。效率最高。（用到了dispatch group）
3.如果要通过遍历。通过一定的条件筛选得到一些数据。可以使用rac_sequence方法。直接获得。
4.要想有序的遍历可以使用enumerateObjectsUsingBlock更加清晰直观。但是比for稍微慢一点。
二、字典遍历
1.利用allKeys进行遍历
NSMutableDictionary *dic = [NSMutableDictionary dictionary];
for (int i = 0; i < 10000; i++){
[dic setObject:@(i) forKey:@(i)];
}
double allKeyStart = CFAbsoluteTimeGetCurrent();
for (NSNumber * num in [dic allKeys]){
NSNumber *num = num;
}
double allKeyEnd = CFAbsoluteTimeGetCurrent();
double allKeyUse = allKeyEnd - allKeyStart;
NSLog(@"allKeyUseTime = %f",allKeyUse);
运行结果为：2017-11-11 14:02:41.185373+0800 checkAllThing[4939:109563] allKeyUseTime = 0.000173
2.利用allValues
for (NSNumber *numValue in [dic allValues]){
NSNumber *num = numValue;
}
double dateAllValueEnd = CFAbsoluteTimeGetCurrent();
double dateAllValueUse = dateAllValueEnd - allKeyEnd;
NSLog(@"dateAllValueEnd = %f",dateAllValueUse);
[dic enumerateKeysAndObjectsUsingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {
NSNumber *num = obj;
}];
double dateEnumerateNoOptionEnd = CFAbsoluteTimeGetCurrent();
double dateEnumerationNoOptionUse = dateEnumerateNoOptionEnd - dateAllValueEnd;
NSLog(@"dateEnumerateNoOptionUse = %f",dateEnumerationNoOptionUse);
运行结果为：
2017-11-11 14:02:41.185776+0800 checkAllThing[4939:109563] dateAllValueEnd = 0.000449
3.使用enumerateKeysAndObjectsWithOptions进行遍历
[dic enumerateKeysAndObjectsUsingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {
NSNumber *num = obj;
}];
double dateEnumerateNoOptionEnd = CFAbsoluteTimeGetCurrent();
double dateEnumerationNoOptionUse = dateEnumerateNoOptionEnd - dateAllValueEnd;
NSLog(@"dateEnumerateNoOptionUse = %f",dateEnumerationNoOptionUse);
运行结果为
2017-11-11 14:02:41.186737+0800 checkAllThing[4939:109563] dateEnumerateNoOptionUse = 0.000957
4.使用enumerateKeysAndObjectsWithOptions进行运行
[dic enumerateKeysAndObjectsWithOptions:NSEnumerationConcurrent usingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {
NSNumber *num = obj;
}];
double dateEnumerateOptionEnd = CFAbsoluteTimeGetCurrent();
double dateEnumerationOptionUse = dateEnumerateOptionEnd - dateEnumerateNoOptionEnd;
NSLog(@"dateEnumrateOptionUse%f",dateEnumerationOptionUse);
运行结果为
2017-11-11 14:02:41.187683+0800 checkAllThing[4939:109563] dateEnumrateOptionUse0.000947
运行结果进行总结分析如下
2017-11-11 14:02:41.185373+0800 checkAllThing[4939:109563] allKeyUseTime = 0.000173
2017-11-11 14:02:41.185776+0800 checkAllThing[4939:109563] dateAllValueEnd = 0.000449
2017-11-11 14:02:41.186737+0800 checkAllThing[4939:109563] dateEnumerateNoOptionUse = 0.000957
2017-11-11 14:02:41.187683+0800 checkAllThing[4939:109563] dateEnumrateOptionUse0.000947
1.运行分析发现使用allKeys进行遍历效率最高。
2.通过enumrateOption方法可以清晰直观的查看key和value值。
三、集合处理
NSSet *set = [NSSet setWithObjects:@"12",@"32",@"2",@"12", nil];
[set enumerateObjectsUsingBlock:^(id _Nonnull obj, BOOL * _Nonnull stop) {
NSLog(@"%@",obj);
}];
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