scala - ReduceLeft with Vector of pairs? -

i have vector of pairs

vector((9,1), (16,2), (21,3), (24,4), (25,5), (24,6), (21,7), (16,8), (9,9), (0,10)) 

and want return pair maximum first element in pair. i've tried this:

data reduceleft[(int, int)]((y:(int, int),z:(int,int))=>y._1 max z._1) 

and

data reduceleft((y:(int, int),z:(int,int))=>y._1 max z._1) 

but there type mismatch error , can't understand wrong code.

why using reduceleft ? default max method works well

scala> val v = vector((9,1), (16,2), (21,3), (24,4), (25,5), (24,6), (21,7), (16,8), (9,9), (0,10)) v: scala.collection.immutable.vector[(int, int)] = vector((9,1), (16,2), (21,3), (24,4), (25,5), (24,6), (21,7), (16,8), (9,9), (0,10))  scala> v.max  res1: (int, int) = (25,5) 

if want reduceleft instead :

v.reduceleft( (x, y) => if (x._1 >= y._1) x else y ) 

your error have return tuple, not int

y._1 max z._1 

the max function here on 2 int return int.