Formatting Decimal places in R

Question

I have a number  for example 1 128347132904321674821 that I would like to show as only two decimal places when output to screen  or written to a file   How does one do that    x  lt - 1 128347132904321674821   EDIT    The use of    options digits 2    Has been suggested as a possible answer  Is there a way to specify this within a script for one-time use  When I add it to my script it doesn t seem to do anything different and I m not interested in a lot of re-typing to format each number  I m automating a very large report     --   Answer  round x  digits 2

User · Accepted Answer

Background  Some  answers suggested on this page  e g   signif  options digits       do not guarantee that a certain number of decimals are displayed for an arbitrary number  I presume this is a design feature in R whereby good scientific practice involves showing a certain number of digits based on principles of  significant figures   However  in many domains  e g   APA style  business reports  formatting requirements dictate that a certain number of decimal places are displayed  This is often done for consistency and standardisation purposes rather than being concerned with significant figures   Solution   The following code shows exactly two decimal places for the number x   format round x  2   nsmall   2    For example   format round 1 20  2   nsmall   2     1   1 20  format round 1  2   nsmall   2     1   1 00  format round 1 1234  2   nsmall   2     1   1 12    A more general function is as follows where x is the number and k is the number of decimals to show  trimws removes any leading white space which can be useful if you have a vector of numbers   specify decimal  lt - function x  k  trimws format round x  k   nsmall k     E g    specify decimal 1234  5     1   1234 00000  specify decimal 0 1234  5     1   0 12340

User · Answer

if you just want to round a number or a list  simply use   round data  2    Then  data will be round to 2 decimal place

User · Answer

You can try my package formattable    gt    devtools  install github  renkun-ken formattable    gt  library formattable   gt  x  lt - formattable 1 128347132904321674821  digits   2  format    f    gt  x  1  1 13   The good thing is  x is still a numeric vector and you can do more calculations with the same formatting    gt  x   1  1  2 13   Even better  the digits are not lost  you can reformat with more digits any time      gt  formattable x  digits   6  format    f    1  1 128347

User · Answer

You can format a number  say x  up to decimal places as you wish  Here x is a number with many decimal places  Suppose we wish to show up to 8 decimal places of this number   x   1111111234 6547389758965789345 y   formatC x  digits   8  format    f      1   1111111234 65473890    Here format  f  gives floating numbers in the usual decimal places say  xxx xxx  and digits specifies the number of digits  By contrast  if you wanted to get an integer to display you would use format  d   much like sprintf

User · Answer

here s my approach from units to millions  digits parameter let me  adjust the minimum number of significant values  integer   decimals   You could adjust decimal rounding inside first  number  lt -function number     result  lt - if else      abs number   lt  1000000      format        number  digits   3        big mark    quot   quot         decimal mark    quot   quot             paste0        format          number 1000000          digits   3          drop0trailing   TRUE          big mark    quot   quot           decimal mark    quot   quot                  quot MM quot                result  lt - paste0  quot   quot   result    return result

User · Answer

Note that numeric objects in R are stored with double precision  which gives you  roughly  16 decimal digits of precision - the rest will be noise  I grant that the number shown above is probably just for an example  but it is 22 digits long

User · Answer

The function formatC   can be used to format a number to two decimal places  Two decimal places are given by this function even when the resulting values include trailing zeros

User · Answer

If you prefer significant digits to fixed digits then  the signif command might be useful    gt  signif 1 12345  digits   3   1  1 12  gt  signif 12 12345  digits   3   1  12 1  gt  signif 12345 12345  digits   3   1  12300

User · Answer

Looks to me like to would be something like   library tutoR  format 1 128347132904321674821  2    Per a little online help

User · Answer

I m using this variant for force print K decimal places     format numeric value to K decimal places formatDecimal  lt - function x  k  format round x  k   trim T  nsmall k

User · Answer

Check functions prettyNum  format  to have trialling zeros  123 1240 for example  use sprintf x  fmt     4g

User · Answer

Something like that    options digits 2    Definition of digits option    digits  controls the number of digits to print when printing numeric values

User · Answer

for 2 decimal places assuming that you want to keep trailing zeros  sprintf 5 5  fmt       2f     which gives   1   5 50    As  mpag mentions below  it seems R can sometimes give unexpected values with this and the round method e g  sprintf 5 5550  fmt     2f   gives 5 55  not 5 56

[r] Formatting Decimal places in R

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