Best Way to Find the smallest and biggest value in NSArray of NSNumbers

I made tests with an array of 1000000 random numbers:

Suppose we have numbers is an array having 1000000 number object

Method 1: sort the array:

NSArray *sorted1 = [numbers sortedArrayUsingSelector:@selector(compare:)]; took 1.585 seconds

Method 2 : Key-value coding, using "doubleValue":

NSNumber *max=[numbers valueForKeyPath:@"@max.doubleValue"];

NSNumber *min=[numbers valueForKeyPath:@"@min.doubleValue"]; took 0.778 seconds

Method 3: Key-value coding, using "self":

NSNumber *max=[numbers valueForKeyPath:@"@max.self"];

NSNumber *min=[numbers valueForKeyPath:@"@min.self"]; took 0.390 seconds

Method 4: Block enumeration:

__block float xmax = -MAXFLOAT;

__block float xmin = MAXFLOAT;

[numbers enumerateObjectsUsingBlock:^(NSNumber *num, NSUInteger idx, BOOL *stop) {

    float x = num.floatValue;

    if (x < xmin) xmin = x;

    if (x > xmax) xmax = x;

}];

took 0.024 seconds

Method 5: Explicit loop:

float xmax = -MAXFLOAT;

float xmin = MAXFLOAT;

for (NSNumber *num in numbers) {

    float x = num.floatValue;

    if (x < xmin) xmin = x;

    if (x > xmax) xmax = x;

} took 0.019 seconds

So, if execution speed  is important, then an explicit loop is the fastest.

#iOS #Girijesh #Xcode #iPhone