这个循环非常慢，我想因为我创建了很多中间字符串。如何加速？ [英] This loop is very slow, I think because I create a lot of intermediate strings. How can I speed it up?

问题描述

NSArray *splitPoints = [routeGeom componentsSeparatedByString:@"], ["];
routePoints = malloc(sizeof(CLLocationCoordinate2D) * ([splitPoints count] + 1));

int i=0;
NSArray *coords; 
for (NSString* coordStr in splitPoints) {

  coords = [coordStr componentsSeparatedByString:@","];

  routePoints[i].latitude = [[[coords objectAtIndex:0] substringFromIndex:1]floatValue];
  routePoints[i].longitude = [[coords objectAtIndex:1] floatValue];

  i++;

}
[coords release];

NSLog(@"** Time to split the route geometry into structs %f", [NSDate timeIntervalSinceReferenceDate] - start);

推荐答案

请考虑：

char *buf = [coordStr UTF8String];
sscanf(buf, "%f,%f", &routePoints[i].latitude, routePoints[i].longitude);

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