Re: Use of blocks
Re: Use of blocks
- Subject: Re: Use of blocks
- From: Preston Sumner <email@hidden>
- Date: Mon, 12 Jul 2010 02:32:50 -0600
You can use key-path collection operators, assuming someTrips is a property of self:
NSNumber *minPrice = [self valueForKeyPath:@"email@hiddenFinalPrice"];
NSNumber *maxPrice = [self valueForKeyPath:@"email@hiddenFinalPrice"];
By the way, minValue and maxValue in your example need to be declared with __block or they'll be captured as read-only constants.
Preston Sumner
On Jul 12, 2010, at 1:34 AM, Giannandrea Castaldi wrote:
> Hi,
> I want to use blocks to extract the min price and the max price from
> an NSArray of trips. I've found the following way:
>
> float minValue = 0.0;
> [someTrips enumerateObjectsUsingBlock:^(id obj, NSUInteger idx,
> BOOL *stop) {
> if (minValue == 0.0 || [[obj adultFinalPrice] floatValue] < minValue) {
> minValue = [obj floatValue];
> }
> }];
> float maxValue = 0.0;
> [someTrips enumerateObjectsUsingBlock:^(id obj, NSUInteger idx,
> BOOL *stop) {
> if (maxValue == 0.0 || [[obj adultFinalPrice] floatValue] > maxValue) {
> maxValue = [obj floatValue];
> }
> }];
>
> I've just begun to use blocks and I wonder if there is a more brief
> way, may be without the need to define the float variables before the
> iterations.
>
> I've also looked for a solution with NSExpression and NSPredicate with
> the function min/max but if I've correctly understood the use of
> NSExpression and NSPredicate with such functions is only for CoreData.
> Thanks.
>
> Jean
> --
> “We are what we repeatedly do. Excellence then, is not an act, but a habit.”
> Aristotle
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| | >Use of blocks (From: Giannandrea Castaldi <email@hidden>) |