LaTeX or Sweave friendly Formatting of Numbers

Formats real numbers, possibly in scientific notation, with a given number of digits after the decimal point. Output can be used in LaTeX math mode, e.g., for printing numbers in a table, where each number has to be printed with the same number of digits after the decimal point, even if the last digits are zeros.

# S3 method for class 'numeric'
toLatex(object, digits = format.info(object)[2],
        scientific = format.info(object)[3] > 0, times = "\\cdot", ...)

Arguments

object: a numeric vector.
digits: number of digits after the decimal point (for the mantissa if scientific). The default behaves the same as R's format().
scientific: logical indicating if scientific notation a * 10^k should be used. The default behaves the same as R's format().
times: character string indicating the LaTeX symbol to be used for the ‘times’ sign.
...: unused; for compatibility with toLatex.

Note

We use digits for round, i.e., round after the decimal point on purpose, rather than signif()icant digit rounding as used by print() or format().

Value

a character vector of the same length as object, containing the formatted numbers.

Author

Alain Hauser

Examples

xx <- pi * 10^(-9:9)

format(xx)
#>  [1] "3.14e-09" "3.14e-08" "3.14e-07" "3.14e-06" "3.14e-05" "3.14e-04"
#>  [7] "3.14e-03" "3.14e-02" "3.14e-01" "3.14e+00" "3.14e+01" "3.14e+02"
#> [13] "3.14e+03" "3.14e+04" "3.14e+05" "3.14e+06" "3.14e+07" "3.14e+08"
#> [19] "3.14e+09"
formatC(xx)
#>  [1] "3.142e-09" "3.142e-08" "3.142e-07" "3.142e-06" "3.142e-05" "0.0003142"
#>  [7] "0.003142"  "0.03142"   "0.3142"    "3.142"     "31.42"     "314.2"    
#> [13] "3142"      "3.142e+04" "3.142e+05" "3.142e+06" "3.142e+07" "3.142e+08"
#> [19] "3.142e+09"

toLatex(xx) #-> scientific = TRUE is chosen
#>  [1] "3.14 \\cdot 10^{-9}" "3.14 \\cdot 10^{-8}" "3.14 \\cdot 10^{-7}"
#>  [4] "3.14 \\cdot 10^{-6}" "3.14 \\cdot 10^{-5}" "3.14 \\cdot 10^{-4}"
#>  [7] "3.14 \\cdot 10^{-3}" "3.14 \\cdot 10^{-2}" "3.14 \\cdot 10^{-1}"
#> [10] "3.14 \\cdot 10^{0}"  "3.14 \\cdot 10^{1}"  "3.14 \\cdot 10^{2}" 
#> [13] "3.14 \\cdot 10^{3}"  "3.14 \\cdot 10^{4}"  "3.14 \\cdot 10^{5}" 
#> [16] "3.14 \\cdot 10^{6}"  "3.14 \\cdot 10^{7}"  "3.14 \\cdot 10^{8}" 
#> [19] "3.14 \\cdot 10^{9}" 
toLatex(xx, scientific=FALSE)
#>  [1] "0.00"          "0.00"          "0.00"          "0.00"         
#>  [5] "0.00"          "0.00"          "0.00"          "0.03"         
#>  [9] "0.31"          "3.14"          "31.42"         "314.16"       
#> [13] "3141.59"       "31415.93"      "314159.27"     "3141592.65"   
#> [17] "31415926.54"   "314159265.36"  "3141592653.59"

sapply(xx, toLatex)
#>  [1] "3.14 \\cdot 10^{-9}" "3.14 \\cdot 10^{-8}" "3.14 \\cdot 10^{-7}"
#>  [4] "3.14 \\cdot 10^{-6}" "3.14 \\cdot 10^{-5}" "0.000314"           
#>  [7] "0.00314"             "0.0314"              "0.314"              
#> [10] "3.14"                "31.4"                "314"                
#> [13] "3142"                "31416"               "314159"             
#> [16] "3141593"             "31415927"            "3.14 \\cdot 10^{8}" 
#> [19] "3.14 \\cdot 10^{9}" 
sapply(xx, toLatex, digits = 2)
#>  [1] "3.14 \\cdot 10^{-9}" "3.14 \\cdot 10^{-8}" "3.14 \\cdot 10^{-7}"
#>  [4] "3.14 \\cdot 10^{-6}" "3.14 \\cdot 10^{-5}" "0.00"               
#>  [7] "0.00"                "0.03"                "0.31"               
#> [10] "3.14"                "31.42"               "314.16"             
#> [13] "3141.59"             "31415.93"            "314159.27"          
#> [16] "3141592.65"          "31415926.54"         "3.14 \\cdot 10^{8}" 
#> [19] "3.14 \\cdot 10^{9}"