R - Adding numbers within a data frame cell together - r

Question

I have a data frame in which the values are stored as characters. However, many values contain two numbers that need to be added together. Example:
2014 Q1 Sales 2014 Q2 Sales 2014 Q3 Sales 2014 Q4 Sales
Product 1 3+6 2+10 8 13+2
Product 2 6 4+0 <NA> 5
Product 3 <NA> 5+9 3+1 11
Is there a way to go through the whole data frame and replace all cells containing characters like "3+6" with new values equal to their sum? I assume this would involve coercing the characters to numeric or integers, but I don't know how that would be possible for values with the + sign in them. I would like the example data frame to end up looking like this:
2014 Q1 Sales 2014 Q2 Sales 2014 Q3 Sales 2014 Q4 Sales
Product 1 9 12 8 15
Product 2 6 4 <NA> 5
Product 3 <NA> 14 4 11

Answer 1

Here's an easier example:
dat <- data.frame(a=c("3+6", "10"), b=c("12", NA), c=c("3+4", "5+6"))
dat
## a b c
## 1 3+6 12 3+4
## 2 10 <NA> 5+6
apply(dat, 1:2, function(x) eval(parse(text=x)))
## a b c
## [1,] 9 12 7
## [2,] 10 NA 11
Using R itself to do the computation with eval and parse does the trick.

Answer 2

Here is one option with gsubfn without using eval(parse. We convert the 'data.frame' to 'matrix' (as.matrix(dat)). We match the numbers ([0-9]+), capture it as a group using parentheses ((..)) followed by +, followed by second set of numbers, and replace it by converting to numeric class and then do the +. The output can be assigned back to the original dataset to get the same structure as in 'dat'.
library(gsubfn)
dat[] <- as.numeric(gsubfn('([0-9]+)\\+([0-9]+)',
~as.numeric(x)+as.numeric(y), as.matrix(dat)))
dat
# 2014 Q1 Sales 2014 Q2 Sales 2014 Q3 Sales 2014 Q4 Sales
#Product 1 9 12 8 15
#Product 2 6 4 NA 5
#Product 3 NA 14 4 11
Or we can loop the columns with lapply and perform the replacement with gsubfn for each of the columns.
dat[] <- lapply(dat, function(x) as.numeric(gsubfn('([0-9]+)\\+([0-9]+)',
~as.numeric(x)+as.numeric(y), as.character(x))))
data
dat <- structure(list(`2014 Q1 Sales` = structure(c(1L, 2L, NA), .Label = c("3+6",
"6"), class = "factor"), `2014 Q2 Sales` = structure(1:3, .Label = c("2+10",
"4+0", "5+9"), class = "factor"), `2014 Q3 Sales` = structure(c(2L,
NA, 1L), .Label = c("3+1", "8"), class = "factor"), `2014 Q4 Sales` = structure(c(2L,
3L, 1L), .Label = c("11", "13+2", "5"), class = "factor")), .Names = c("2014 Q1 Sales",
"2014 Q2 Sales", "2014 Q3 Sales", "2014 Q4 Sales"), class = "data.frame", row.names = c("Product 1",
"Product 2", "Product 3"))