R使用特殊字符

Question

I have a column of strings (and NAs) in a dataset whose values look like:

"85min"  "1hr 19min"  "98min"  NA  "119min"  "105min"  NA  "1hr 30min"

I'm trying to change all of the values to numerics (in minutes), so that the values look like:

85  79  98  NA  119  105  NA  90

I tried to do it by pieces, first removing the "min," then removing the "hr," then changing "1" to "60," and then changing the middle spaces to plus signs, giving me:

"85"  "60+19"  "98"  NA  "119"  "105"  NA  "60+30"

I was hoping that by applying as.numeric, I would get the ones with "+" signs to turn into formulas, but instead they just resulted in NAs.

Is there any shorthand way of doing this kind of conversion? Many thanks in advance!

Answer 1

Yes, you need parse and eval

strings = c("85",  "60+19",  "98",  NA,  "119",  "105",  NA,  "60+30")
sapply(parse(text=strings), eval)
[1]  85  79  98  NA 119 105  NA  90