How to write numbers in scientific notation in R

Question

I am wondering if there is a way to write 0.000523 in scientific notation ( 5.23x10^-4) in R. I am using the xtable command to write a table into latex.

`format(x, scientific = T)` gives `1] "5.23e-04"` – joel.wilson Jan 06 '17 at 08:16 — joel.wilson, Jan 06 '17 at 08:16
You can use `options(scipen = -15)` – akrun Jan 06 '17 at 08:18 — akrun, Jan 06 '17 at 08:18

score 4 · Answer 1 · answered Jan 06 '17 at 08:36

4

You can use sprintf like this:

x <- c(0.000523, -523)

sprintf("%.2fx10^{%d}", 
        x/10^floor(log10(abs(x))), 
        floor(log10(abs(x))))
#[1] "5.23x10^{-4}" "-5.23x10^{2}"

You'll need to write some ifelse conditions to have different formatting depending on the decimal ranges.

answered Jan 06 '17 at 08:36

Roland

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what about `gsub("e", "x10^", format(scientific = T, x))` giving `5.23x10^-04`. though not logically sound step – joel.wilson Jan 06 '17 at 10:24

score 4 · Answer 2 · answered Jan 06 '17 at 08:37

The xtable package offers the function sanitize.numbers() that can do this. It works on characters, so you first have to use format() to convert your numbers to characters:

library(xtable)
sanitize.numbers(format(0.000523, scientific = TRUE),
                 type = "latex", math.style.exponents = TRUE)
## [1] "$5.23 \\times 10^{-4}$"

As you notice, this does not give 5.23x10^-4 but rather the equivalent of this expression in LaTeX notation, which may not be what you needed.

How to write numbers in scientific notation in R

2 Answers2