Xjyuk

I am new to LaTeX and found a helpful custom command for repeating text n times here. Below is an example use

documentclassminimal
usepackagepgffor
newcommandmyrepeat[2]foreach n in 1,...,#1#2

begindocument
myrepeat6x % prints xxxxxx
enddocument

My goal is to pass a decimal number as the first argument to the command (as opposed to an integer currently). The for-loop in the command should round the decimal to determine how many iterations to execute. This way I can universally change the rounding mode (i.e. floor, ceiling, closest integer, etc) later just by updating the one command. For instance

myrepeat3.2x % should print xxx
myrepeat3.7x % should print xxxx

How can I achieve this behavior?

Most other threads I have seen only deal with printing rounding/ceiling/floor symbols instead of actually performing the rounding math and allowing you to use the resulting number in further computations.

One approach would be this. ceil and floor are alternatives to round. There are also command versions of each, as Alan Munn mentions in a comment, i.e. pgfmathround#1, pgfmathceil#1, pgfmathfloor#1.

documentclassarticle
usepackagepgffor
newcommandmyrepeat[2]%
 pgfmathparseround(#1)% set rounding function here
 foreach n in 1,...,pgfmathresult#2

begindocument
myrepeat3.2x % should print xxx

myrepeat3.7x % should print xxxx
enddocument

You can use the expandable functionality of xfp:

documentclassarticle

usepackagepgffor,xfp

newcommandmyrepeat[2]foreach n in 1,...,fpevalfloor(#1)#2

begindocument

myrepeat6x % prints xxxxxx

myrepeat3.2x % prints xxx

myrepeat8.1 * sin(pi / 6)x% prints xxxx sin(pi/6) = 1/2; 8.1 * 1/2 = 4.05

enddocument

You can use ceiling(#1), or round(#1,0), or whatever calculation you want.

Here's a fairly general macro where you can set the mode as an optional argument: choose between round (default), floor, ceil or nearest.

The generalrepeat macro accepts the starting point (an integer), the step (an integer, default 1) and the end point (a floating point number).

The myrepeat macro is a reduced version, always starting from 1 with step 1.

In the final argument (code to repeat), the current value in the loop is denoted by #1.

documentclassarticle
usepackagexfp

ExplSyntaxOn
NewDocumentCommandgeneralrepeat
 
 Oround % the mode
 m % the starting point
 O1 % the step
 m % the final point
 +m % the code to repeat (can contain par)
 
 
 klinke_repeat_general:nnnnn #1 #2 #3 #4 #5 
 

NewDocumentCommandmyrepeat
 
 Oround % the mode
 m % the final point
 +m % the code to repeat (can contain par)
 
 
 klinke_repeat_general:nnnnn #1 1 1 #2 #3 
 

cs_new_protected:Nn klinke_repeat_general:nnnnn
 
 cs_set_eq:Nc __klinke_repeat_mode:n __klinke_repeat_#1:n 
 cs_set_protected:Nn __klinke_repeat_code:n #5 
 int_step_function:nnnN
 #2 % start
 #3 % step
 __klinke_repeat_mode:n #4 % end
 __klinke_repeat_code:n % action
 

cs_new:Nn __klinke_repeat_round:n fp_eval:n round(#1,0,1) 
cs_new:Nn __klinke_repeat_floor:n fp_eval:n floor(#1,0) 
cs_new:Nn __klinke_repeat_ceil:n fp_eval:n ceil(#1,0) 
cs_new:Nn __klinke_repeat_nearest:n
 
 fp_eval:n #1 - floor(#1,0) < 0.5 ? floor(#1,0) : ceil(#1,0) 
 
ExplSyntaxOff

begindocument

generalrepeat13.4#1 ---
generalrepeat13.5#1 ---
generalrepeat13.6#1 

generalrepeat[ceil]13.4#1 ---
generalrepeat[ceil]13.5#1 ---
generalrepeat[ceil]13.6#1 

generalrepeat[floor]13.4#1 ---
generalrepeat[floor]13.5#1 ---
generalrepeat[floor]13.6#1 

generalrepeat[nearest]13.4#1 ---
generalrepeat[nearest]13.5#1 ---
generalrepeat[nearest]13.6#1 

myrepeat3.4x---myrepeat[floor]3.4x---%
myrepeat[ceil]3.4x---myrepeat[nearest]3.4x

myrepeat3.5x---myrepeat[floor]3.5x---%
myrepeat[ceil]3.5x---myrepeat[nearest]3.5x

myrepeat3.6x---myrepeat[floor]3.6x---%
myrepeat[ceil]3.6x---myrepeat[nearest]3.6x

enddocument

Both round and nearest integer are implemented to go upward in case of a tie (the 3.5 case).