I have a dataframe that involves several columns, in which there are many instances where inequalities are present. What I would like to have, is an R script that will identify these inequalities and replace them with actual values. More specific, let's assume that we have "<2" and we want to replace it with its half value ("<2" -> 1.0). Is there a generic way to do it so that I do not need to find manually all the inequalities within the dataframe and replace them?
A simple example might be the following:
Col1,Col2, Col3, Col4
2.2, <3, 4,<2
3.4, 4, <5,3
4.2, 2,2.1,5
1.3, 1,4,<8
And I want to get something like this:
Col1,Col2,Col3,Col4
2.2, 1.5, 4,1
3.4, 4, 2,5,3
4.2, 2,2.1,5
1.3, 1,4,4
We can replace the < with an expression and evaluate
df1[] <- lapply(df1, function(x) sapply(sub("<", "(1/2)*", x, fixed = TRUE),
function(y) eval(parse(text = y))))
df1
# Col1 Col2 Col3 Col4
#1 2.2 1.5 4.0 1
#2 3.4 4.0 2.5 3
#3 4.2 2.0 2.1 5
#4 1.3 1.0 4.0 4
df1 <- structure(list(Col1 = c(2.2, 3.4, 4.2, 1.3), Col2 = c("<3", "4",
"2", "1"), Col3 = c("4", "<5", "2.1", "4"), Col4 = c("<2", "3",
"5", "<8")), row.names = c(NA, -4L), class = "data.frame")