Re: Printing numbers

*To*: mathgroup at smc.vnet.net*Subject*: [mg54576] Re: Printing numbers*From*: dh <dh at metrohm.ch>*Date*: Wed, 23 Feb 2005 03:11:48 -0500 (EST)*References*: <cvc887$qsa$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi Steve, Steve Gray wrote: > 1. Can anyone tell me why these results are what they are? Neither answer is what I would expect, > which is 10. The two strings are the same length. > > Print[StringLength[ToString[123.456789]], " ", > StringLength[ToString[1234567.89]]]; > 7 22 > By default, ToString formats according to the OutputForm in effect. You can simply check this by looking at the result of ToString[..]. This gives 123.457 and " 6\n1.23457 10" The first is truncated because Mathematica by default prints 6 digits. The second is actually a 2 dimensional output, what explains its length. To get what you want, you could use InputForm or NumberForm, each has its little pitfalls. > 2. Is there a simple, easily available or self-evident way to get numbers printed out such that the > total number of spaces occupied by the print before the decimal point is some fixed, user-specified > amount, the number of spaces occupied after the decimal point is a different user-specified amount, > and the number of spaces following the number is a third user-specified amount. The goal is to > easily produce aligned columns of numerical printing, which would seem to be the most trivial task > in neat number printing. > For example if the function is called fprint, fprint[345.678,4,5,6] would print 4 spaces > followed by 5 character positions to the left of the point (00345 or (2 spaces)" 345", specified by > another argument), and 6 to its right. So fprint[345.678,4,5,6] would print (4 spaces)(2 > spaces)"345.678"(3 spaces), or if desired (4 spaces)(2 spaces)"345.678000"(no spaces), the total > taking up 16 positions. Also fprint[-345.678,4,5,6] would print (4 spaces)(1 space)"-345.678"(3 > spaces), also taking 16 positions, with the decimal points aligned with the first example. > Help is not that helpful, implying that I have to write one or find it somewhere. As I > recall, C provides an easy way to do this by setting arguments to Print. > Leads would be appreciated. Closest to what you want seems NumberForm. To occupy empty places you need the option "NumberPadding". e.g.: NumberForm[3.1234567, {20, 10}, NumberPadding -> {"-", "-"}] gives: ----------3.1234567--- Note a quirck, the number of digits is always too big by one.