Question

I have this data set

  names age height weight
1   joe  23    170     65
2  jack  25    173     73
3   jim  27    168     71
4 james  23    172     70

and I want to get all the info for people under 173 height, so I do this

short <- c(t(subset(dfD, height < 173, select = names)))

short returns this

[1] "joe" "jim" "jack"

But when I try to get all the data from that list…

dfD[(dfD[1] == short),]

it returns only this

  names age height weight
1   joe  23    170     65

How can I get this to work?

I want to be able to create name lists and get all their data that way…how is it possible?

Answer 1

subset() and dlply() will select a subset of a data frame, and change the data frame into a list. Is this what you want?

## Your data
df = read.table(text = "  names age height weight
  joe  23    170     65
  jack  25    173     73
  jim  27    168     71
  james  23    172     70", header = TRUE, sep = "")

  library(plyr) 
   short = subset(df, height < 173)
  data.list = dlply(short, "names")

OR

  short = subset(df, height < 173, "names")
  subset(df, names %in% short[[1]])