Force R not to use exponential notation (e.g. e+10

问题:

Can I force R to use regular numbers instead of using the e+10-like notation? I have:

1.810032e+09
# and 
4

within the same vector and want to see:

1810032000
# and
4

I am creating output for an old fashioned program and I have to write a text file using cat. That works fine so far but I simply can\'t use the e+10 notation there.

回答1:

This is a bit of a grey area. You need to recall that R will always invoke a print method, and these print methods listen to some options. Including \'scipen\' -- a penalty for scientific display. From help(options):

‘scipen’: integer. A penalty to be applied when deciding to print numeric values in fixed or exponential notation. Positive values bias towards fixed and negative towards scientific notation: fixed notation will be preferred unless it is more than ‘scipen’ digits wider.

Example:

R> ran2 <- c(1.810032e+09, 4) 
R> options(\"scipen\"=-100, \"digits\"=4)
R> ran2
[1] 1.81e+09 4.00e+00
R> options(\"scipen\"=100, \"digits\"=4)
R> ran2
[1] 1810032000          4

That said, I still find it fudgeworthy. The most dire way is to use sprintf() with explicit width.

回答2:

It can be achieved by disabling scientific notation in R.

options(scipen = 999)

回答3:

My favorite answer:

format(1810032000, scientific = FALSE)
# [1] \"1810032000\"

This gives what you want without having to muck about in R settings.

Note that it returns a character string rather than a number object

回答4:

Put options(scipen = 999) in your .Rprofile file so it gets auto-executed by default. (Do not rely on doing it manually.)

(This is saying something different to other answers: how?

1. This keeps things sane when you think between multiple projects, multiple languages on a daily or monthly basis. Remembering to type in your per-project settings is error-prone and not scalable. You can have a global ~/.Rprofile or per-project .Rprofile. Or both, with the latter overriding the former.
2. Keeping all your config in a project-wide or global .Rprofile auto-executes it. This is useful for e.g. default package loads, data.table configuration, environment etc. Again, that config can run to a page of settings, and there\'s zero chance you\'ll remember those and their syntax and type them in