printf formatting date time floats

[Dave]

What support does kdb have for handling and formatting numbers? dates?

Often I find myself asked by the users to provide “nicely” formatted numbers and have to suggest they handle that on their end in excel or C#.

Am I missing something? What is available?

[Ryan Hamilton]

For formatting numbers especially floats with decimal places there are two useful functions .Q.fmt and .Q.f

.Q.fmt [x;y] – takes two arguments, x the total number of characters, y the number of decimal places.

q).Q.fmt[6;2]each 1 2.1 3.45678 200 2000
" 1.00"
" 2.10"
" 3.46"
"200.00"
"******"


.Q.f – takes one argument, the number of decimal places to show.

q)\P 0
q).Q.f[2;]each 9.996 34.3445 7817047037.90 781704703567.90 -.02 9.996 -0.0001
"10.00"
"34.34"
"7817047037.90"
"781704703567.90"
"-0.02"
"10.00"
"-0.00"


Notice \P is used here to control the precision of floating point numbers, it affects many areas throughout kdb (saving as csv, web browser…). Also notice that I needed to use each with both these functions as they operate on atoms.

[Dave]

That is useful but is there no printf?

[admin]

You could import printf like functionality using a C shared library (windows DLL, Linuz .so)

[Author]

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