CODEWITHSUNDEEP
r
Duncan
Duncan

Reputation: 1034

Using subset function with variable columns?

I'm using the subset function in R and I'm wondering if there's a way for me to define the column name as a variable, and then subset that column name?

For example, right now I have something like this:

data.subset <- subset(df, age >= n1 & age < n2)

But say I wanted to subset on height instead of age. I want to have a variable that I can just set to "height" and the subset will subset on height instead. I'm doing this to have a function that is adaptable. Something like this:

my.column <- "height"
data.subset <- subset(df, my.column >= n1 & my.column < n2)

Upvotes: 2

Views: 460

Answers (1)

Ben Bolker
Ben Bolker

Reputation: 226162

If you insist on using subset you can mess around with eval(parse(text=paste(...))) (ugh!) but given what you're trying to do, subset will be more trouble than it's worth.

my.column <- "height"
data.subset <- df[df[[my.column]] >= n1 & df[[my.column]] < n2),]

You could make this a little bit more compact by defining a between function:

between <- function(x,val1,val2) x>=val1 & x < val2
df[between(df[[my.column]],n1,n2),]

Upvotes: 4

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