[Boost-users] Re: Defining less on member variables/functions

I can't speak for the original poster, but I often have a collection of pairs of the form (time, data) and want to put the whole thing in chronological order. Victor A. Wagner Jr. wrote:

why do you want to sort ONLY on the 1st element of the pair?

At Thursday 2004-03-25 11:34, you wrote:

...

content-class: urn:content-classes:message Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C41297.D800D40A"

I've had this same pattern come up 4 or 5 times now, and each time I've been unable to find a stl + boost solution that allowed me to do what I want without writing my own less function. Basically, I want something that will let me do a sort, or define a map on structs or pairs without writing a less that compares the member variable or ..first. My last attempt:

vector> myVector std::sort(myVector.begin(), myVector.end(), _1.first < _2.first);

No such luck. It looks like I can do operator * and & on lambda objects, but not access members through them. Is there anything in boost, stl, or elsewhere that lets me not write this:

class myLess { bool operator() (pair a, pairb) {return a.first < b.first;} }

Thanks for any help, Chris

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Victor A. Wagner Jr. http://rudbek.com The five most dangerous words in the English language: "There oughta be a law"