Question

df

 primer exptname concentrate timepoints replicate    day     realConc
    Acan      0hr        55mM          0        b1 011311 0.0002771494
    Actb      0hr        55mM          0        b1 011311 0.0061298654
 Atf7ip2      0hr        55mM          0        b1 011311 0.0015750373
  Atp2c1      0hr        55mM          0        b1 011311 0.0010109867
   Casp6      0hr        55mM          0        b1 011311 0.0035939088
 Col10a1      0hr        55mM          0        b1 011311 0.0133760938
    Acan      0hr        55mM          0        b1 011311 0.0002771494
    Actb      0hr        55mM          0        b1 011311 0.0061298654
 Atf7ip2      0hr        55mM          0        b1 011311 0.0015750373
  Atp2c1      0hr        55mM          0        b1 011311 0.0010109867
   Casp6      0hr        55mM          0        b1 011311 0.0035939088
 Col10a1      0hr        55mM          0        b1 011311 0.0133760938

i Have character vector:

 ges <- c('Acan','Casp6')

I only want rows where $primer == ges

I’ve tried

df[df$primer == ges,]

but it only returns the first rows which equals these two characters as opposed to all rows in the data frame which equal this

I feel like this is ridiculously simple but I’m messing up somewhere basic

Help a brother out

Answer 1

== will do element by element checking of equality. Vector recycling comes into play here; it will check the first element of primer against the first element of ges, the second element of primer against the second element of ges, the third element of primer against the first element of ges (due to the recycling) and so on and so forth. What you actually want is to use the %in% operator to check if the elements of primer are in the vector ges.

df[df$primer %in% ges,]