as.numeric with comma decimal separators?

Question

I have a large vector of strings of the form:

Input = c(\"1,223\", \"12,232\", \"23,0\")

etc. That\'s to say, decimals separated by commas,

Answer 1

Building on @adibender solution:

input = '23,67'
as.numeric(gsub(
                # ONLY for strings containing numerics, comma, numerics
                "^([0-9]+),([0-9]+)$", 
                # Substitute by the first part, dot, second part
                "\\1.\\2", 
                input
                ))

I guess that is a safer match...

Answer 2

The answer by adibender does not work when there are multiple commas.

In that case the suggestion from use554546 and answer from Deena can be used.

Input = c("1,223,765", "122,325,000", "23,054")
as.numeric(gsub("," ,"", Input))

ouput:

[1] 1223765 122325000 23054

The function gsub replaces all occurances. The function sub replaces only the first.

Answer 3

As stated by , it's way easier to do this while importing a file. Thw recently released reads package has a very useful features, locale, well explained here, that allows the user to import numbers with comma decimal mark using locale = locale(decimal_mark = ",") as argument.

Answer 4

The readr package has a function to parse numbers from strings. You can set many options via the locale argument.

For comma as decimal separator you can write:

readr::parse_number(Input, locale = readr::locale(decimal_mark = ","))

Answer 5

scan(text=Input, dec=",")
## [1]  1.223 12.232 23.000

But it depends on how long your vector is. I used rep(Input, 1e6) to make a long vector and my machine just hangs. 1e4 is fine, though. @adibender's solution is much faster. If we run on 1e4, a lot faster:

Unit: milliseconds
         expr        min         lq     median         uq        max neval
  adibender()   6.777888   6.998243   7.119136   7.198374   8.149826   100
 sebastianc() 504.987879 507.464611 508.757161 510.732661 517.422254   100

Answer 6

Also, if you are reading in the raw data, the read.table and all the associated functions have a dec argument. eg:

read.table("file.txt", dec=",")

When all else fails, gsub and sub are your friends.