R: find row by two values

Question

I am trying to find in a table a row which matches two column values. I know that I can use which function:

my_data[which(my_data$col1 == "val"),]

But how do I do this for 2 or more values? I've already tried && operator in any order, still doesn't help.

`&` works well with vectors, `&&` doesn't. See https://stackoverflow.com/q/6558921/4996248 — John Coleman, Sep 25 '17 at 22:37
Essentially this is a join operation too - `merge(mtcars, list(cyl=6, gear=4))` for instance. — thelatemail, Sep 25 '17 at 23:47
Very similar to https://stackoverflow.com/questions/38493031/r-pass-a-list-of-filtering-conditions-into-a-dataframe/38493329 too. — thelatemail, Sep 26 '17 at 03:18

score 5 · Answer 1 · answered Sep 25 '17 at 22:39

Using the filter function in dplyr you can do this without too much trouble. Try something like this:

my_data %>%
  filter(col1 == "val", col2 == "other")

By default, you have two or more statements, filter treats it as an AND, but you can be more explicit & like so

my_data %>%
  filter(col1 == "val" & col2 == "other")

score 3 · Accepted Answer · answered Sep 25 '17 at 22:41

3

my_data[which(my_data$col1 == "val" & my_data$col2 == "val2"),] ought to work in base R.

answered Sep 25 '17 at 22:41

lebelinoz

1

this actually works. It's strange, but it was not working because I had one column named with my_data$T , somehow "T" is glitching – Igor Konoplyanko Sep 28 '17 at 19:57

score 2 · Answer 3 · answered Sep 25 '17 at 22:58

2

You can use subset in base R:

subset(my_data, col1 == "val" & col2 == "char")

answered Sep 25 '17 at 22:58

M--

3 Answers3