I am new to regular expressions and have no clue how to work with them. I wanted to create a regex for the below piece of text to fetch the min, avg & max time. I would be using them with NSRegularExpression to fetch the range & then the string.
Can someone please help in creating a regex for the below text.
round-trip min/avg/max/stddev = 3.073/6.010/13.312/2.789 ms
Break it down.
I'm assuming you want to get the numeric values out of that string and toss the rest.
First make a regexp to match a number:
\d matches a digit\d* matches zero or more digits\. matches a period(\d*\.\d*) matches zero or more digits, then a period, then zero or more digitsThen turn it into a Cocoa string:
@"(\\d*\\.\\d*)"Then make an NSRegularExpression:
NSError error;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(\\d*\\.\\d*)"
options:NSRegularExpressionCaseInsensitive
error:&error];
Then get an array with all the matches:
NSArray *matches = [regex matchesInString:string
options:0
range:NSMakeRange(0, [string length])];
Then pull out the values:
NSString* minText = [string substringWithRange:[matches[0] range]];
NSString* avgText = [string substringWithRange:[matches[1] range]];
// etc.
I leave it as an exercise to convert these strings into floats. :-)
Update: I found myself so nauseated by the complexity of this that I made a little library I am humbly calling Unsuck which adds some sanity to NSRegularExpression in the form of from and allMatches methods. Here's how you'd use them:
NSRegularExpression *number = [NSRegularExpression from: @"(\\d*\\.\\d*)"];
NSArray *matches = [number allMatches:@"3.14/1.23/299.992"];
Please check out the unsuck source code on github and tell me all the things I did wrong :-)
I know you want a regex, and they are very handy to learn, but it might be a bit heavier lifting than you need for this situation. With that in mind, I am providing an alternative. I am sure someone else will give you a regex as well.
NSString* str = @"round-trip min/avg/max/stddev = 3.073/6.010/13.312/2.789 ms";
NSString* str2 = [str substringFromIndex:32];
NSArray* components = [str2 componentsSeparatedByString:@"/"];
CGFloat min = [[components objectAtIndex:0] doubleValue];
CGFloat avg = [[components objectAtIndex:1] doubleValue];
CGFloat max = [[components objectAtIndex:2] doubleValue];
NSLog(@"min/avg/max: %f/%f/%f",min,avg,max);
I managed this by using (.*) = (.+?)/(.+?)/(.+?)/(.*)
