On Feb 2, 2011, at 3:48 AM, Asan Ramzan wrote:
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:
I've tried tapply
tapply(GPR119data$responce, GPR119data$GPR119a, max)
Error in tapply(GPR119data$responce, GPR119data$GPR119a, max) :
arguments must have same length
You need to use tapply on the names of the columns , not on the values:
tapply(GPR119data$responce, GPR119data$condition, max)
> tapply(GPR119data$responce, GPR119data$condition, max)
con GPR119a GPR119b GPR119c GPR119d GPR119e GPR119f
0.3350084 0.6451204 0.8240356 0.5729588 0.3099644 0.4677268 1.0184191
Then you can choose the GPR119a value for further examination or
display;
> tapply(GPR119data$responce, GPR119data$condition, max)["GPR119a"]
GPR119a
0.6451204
responce,mouce,condition
I'm guessing from this display that when you read this data in you
used the default separator which is white-space and that does not
include commas. In addition to the above, try adding sep="," in your
read.table function.
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
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and provide commented, minimal, self-contained, reproducible code.
