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I would like to create a function that returns a vector of numbers a precision reflected by having only n significant figures, but without trailing zeros, and not in scientific notation
e.g, I would like
somenumbers <- c(0.000001234567, 1234567.89)
myformat(x = somenumbers, n = 3)
to return
[1] 0.00000123 1230000
I have been playing with format, formatC, and sprintf, but they don't seem to want to work on each number independently, and they return the numbers as character strings (in quotes).
This is the closest that i have gotten example:
> format(signif(somenumbers,4), scientific=FALSE)
[1] " 0.000001235" "1235000.000000000"
945
Precision is the number of digits in a number. Scale is the number of digits to the right of the decimal point in a number. For example, the number 123.45 has a precision of 5 and a scale of 2.
To print a number with a specific number of significant digits we do this: print '{0:1.3g}'. format(1./3.) print '{0:1.3g}'.
Numeric data types can be instructed to format and parse scientific notation only via a pattern. In a pattern, the exponent character immediately followed by one or more digit characters indicates scientific notation. Example: "0. ###E0" formats the number 1234 as "1.234E3".
To specify a level of precision, we need to use a colon ( : ), followed by a decimal point, along with some integer representing the degree of precision. We place this inside the curly braces for an f-string, after the value we want to format.
You can use the signif function to round to a given number of significant digits. If you don't want extra trailing 0's then don't "print" the results but do something else with them.
> somenumbers <- c(0.000001234567, 1234567.89)
> options(scipen=5)
> cat(signif(somenumbers,3),'\n')
0.00000123 1230000
>
sprintf seems to do it:
sprintf(c("%1.8f", "%1.0f"), signif(somenumbers, 3))
[1] "0.00000123" "1230000"
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