How to get summary statistics by group

Question

I m trying to get multiple summary statistics in R S-PLUS grouped by categorical column in one shot  I found couple of functions  but all of them do one statistic per call  like  aggregate     data  lt - c 62  60  63  59  63  67  71  64  65  66  68  66             71  67  68  68  56  62  60  61  63  64  63  59  grp  lt - factor rep LETTERS 1 4   c 4 6 6 8    df  lt - data frame group grp  dt data  mg  lt - aggregate df dt  by df group  FUN mean      mg  lt - aggregate df dt  by df group  FUN sum        What I m looking for is to get multiple statistics for the same group like mean  min  max  std     etc in one call  is that doable

User · Answer

There s many different ways to go about this  but I m partial to describeBy in the psych package   describeBy df dt  df group  mat   TRUE

User · Answer

Besides describeBy  the doBy package is an another option  It provides much of the functionality of SAS PROC SUMMARY  Details   http   www statmethods net stats descriptives html

User · Answer

take a look at the plyr package   Specifically  ddply  ddply df    group   summarise  mean mean dt   sum sum dt

User · Answer

While some of the other approaches work  this is pretty close to what you were doing and only uses base r  If you know the aggregate command this may be more intuitive    with  df   aggregate  dt   by list group    FUN summary

User · Answer

The psych package has a great option for grouped summary stats  library psych       describeBy dt  group  quot grp quot    produces lots of useful stats including mean  median  range  sd  se

User · Answer

after 5 long years I m sure not much attention is going to be received for this answer  But still to make all options complete  here is the one with data table  library data table  setDT df     list mean gr   mean dt   sum gr   sum dt     by     group       group mean gr sum gr  1      A      61    244  2      B      66    396  3      C      68    408  4      D      61    488

User · Answer

Using Hadley Wickham s purrr package this is quite simple  Use split to split the passed data frame into groups  then use map to apply the summary function to each group       library purrr   df   gt   split   group    gt   map summary

User · Answer

I ll put in my two cents for tapply     tapply df dt  df group  summary    You could write a custom function with the specific statistics you want to replace summary

User · Answer

dplyr package could be nice alternative to this problem   library dplyr   df   gt      group by group    gt      summarize mean   mean dt               sum   sum dt     To get 1st quadrant and 3rd quadrant   df   gt      group by group    gt      summarize q1   quantile dt  0 25               q3   quantile dt  0 75

User · Answer

First  it depends on your version of R  If you ve passed 2 11  you can use aggreggate with multiple results functions summary  by instance  or your own function   If not  you can use the answer made by Justin

[r] How to get summary statistics by group

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