[R] (no subject)

[A. Ramzan]

Hello

I am trying to find a way to find the max value, for only a subset of a 
dataframe, depending on how the data is grouped for example,

How would I find the maxmium responce, for all the GPR119a condition below:

responce,mouce,condition
0.105902,KO,con
0.232018561,KO,con
0.335008375,KO,con
0.387025433,KO,GPR119a
0.576769897,KO,GPR119a
0.645120419,KO,GPR119a
0.2538608,KO,GPR119b
0.183061952,KO,GPR119b
0.824035587,KO,GPR119b
0.399201597,KO,GPR119c
0.417006618,KO,GPR119c
0.572958834,KO,GPR119c
0.229467444,KO,GPR119d
0.294089745,KO,GPR119d
0.309964445,KO,GPR119d
0.30474325,KO,GPR119e
0.159374839,KO,GPR119e
0.467726848,KO,GPR119e
1.01841912,KO,GPR119f
0.423028621,KO,GPR119f
0.223588597,KO,GPR119f

Thank