Output from format.default sometimes has whitespace around it when using big.mark="," and trim=TRUE. E.g.: > # works ok as long as big.mark is not actually used: > format(c(-1,1,10,999), big.mark=",", trim=TRUE) [1] "-1" "1" "10" "999" > # but if big.mark is used, output is justified and not trimmed: > format(c(-1,1,10,999,1e6), big.mark=",", trim=TRUE) [1] " -1" " 1" " 10" " 999" "1,000,000" > I am unable to come up with any interpretation of the documentation for format.default under which this output could be considered correct, so I suspect this behavior should be classified as a bug. The last call to 'prettyNum' in format.default has the argument preserve.width = "common" If this is changed to preserve.width = if (trim) "individual" else "common" then output is formatted correctly in the case above. -- Tony Plate > sessionInfo() Version 2.3.1 (2006-06-01) i386-pc-mingw32 attached base packages: [1] "methods" "stats" "graphics" "grDevices" "utils" "datasets" [7] "base" >