How to find the keys of the largest values in Hash R? -

i have hash likes example , create hash using hash package.

how can return keys of maximum values in r ?

input hash table :

h<-hash( keys=c(1,4,5,6),values=c(30,25,25,30) )  # <hash> containing 3 key-value pair(s).  #  1 : 30  #  4 : 25   # 5 : 25  # 6 : 30 

full disclosure: authored , maintain hash package.

unless have hash many key-value pairs , need performance, standard r vectors names better solution. here 1 example:

v <- c(a = 5, b = 2, c = 3, d = 5) names( v[ v==max(v) ] ) 

native r vectors outperform hashes until structure grows beyond ~200 key-value pairs. (it been while since benchmarked hash, vector , list lookup performance).

if hash fits solution, answer @bergant solves op's questions, though please understand rather dangerous. converting hash list , using unlist ignores fact hash values not constrained scalar/atomic values. can r object. consider:

 > hash(a = 1:5, b = 2, c = 3, d=5)  <hash> containing 4 key-value pair(s).  : 1 2 3 4 5  b : 2  c : 3  d : 5 

you can decide whether problem application or not.

a simpler, higher performing , more general approach use 'values' function. in simple case values scalar/atomic values, closely mirrors @bergant's solution.

h <- hash(a = 5, b = 2, c = 3, d = 5) val <- values(h)     # compare `unlist(as.list(h))` names( val[ val == max(val) ] ) 

since values returns named list rather unlisted, set more general solution since can select value compare each key value pair:

h <- hash(a = 1:5, b = 2, c = 3, d=5) val <- values(h)  # alternate 1: compare min each value val <- sapply(val, max )  # alternate 2: compare first element each value  # val <- sapply(val, function(x) x[[1]])  names( val[ val == max(val) ] ) 

i hope helps.