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User:AnatolV/Helper Functions: Difference between revisions
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This page presents only helper functions that are generic enough. They were used in one or more contributions on RC and will be used again and again.<br>
;Note:
Note: Many samples of using these functions can be found here on RC.▼
* Good helper function usually encapsulates typical set of actions for current tasks, supplies often used default values, interacting with other helper functions, etc.
=R Helper Functions=
One of the R's great powers is its unlimited number of great and good packages, virtually thousands of them. For any applications big or small you can find a package.<br>
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* The file names used are without extension (which will be added as ".png", ".dmp" and ".dat" when needed).
* Requesting dump file is useful if the generating/plotting time is big. Having a dump file makes it easy and fast to repeat plotting with different colors, titles, etc.
* If number of generated dots is very big then plotting from a dump file could be very slow too. Actually, plotv2() shows almost "pure" plotting time.<br><br>
{{Works with|R|3.3.1 and above}}
<lang r>
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The problem with these libraries is that they are forcing you to learn, actually, "new" language. In addition, there is no guarantee,
that they would be stable and maintained well.<br>
The good alternative is always to use just 2-3 small helper functions if it is possible for your task.<br>
The same I would suggest JavaScript users about "declarative JavaScript".
It reminds me OOP (Object Oriented Programming) hype! But OOP is dead already, and
now declarative JavaScript is hyped??
Don't let you be foolish again. Remember: you need to learn and use "monster" libraries!?<br><br>
What "declarative JavaScript" is promising (and actually giving you by presented new functions, tags, etc.)?<br>
This is a fantastically sounding: "You are telling JavaScript what to do, but not programming actually".
Think! It is the same as good HFJS is doing! For example, using randhclr() and pmat01() is the same
as "telling JavaScript": "Use random hex color and plot matrix you have". It's just 1 statement: pmat01(mat,randhclr()).<br><br>
In other words, look at these new libraries as a set of good helper functions for your projects.<br>
So, all these new libraries are good for certain type of projects, especially if company
have created this particular library and using it for inner projects. The good such sample is Facebook JavaScript library React.js, which is having/supporting a lot of unique functions and tags. Think again:
do you need all of them?
<lang javascript>
// HFJS#1 Like in PARI/GP: return random number 0..max-1.
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("00"+randgp(256).toString(16)).slice(-2)
}
// HFJS#3: Plot any matrix mat (filled with 0,1)
function pmat01(mat, color) {
// DCLs
var cvs = document.getElementById('canvId');
var ctx = cvs.getContext("2d");
var w = cvs.width; var h = cvs.height;
var m = mat[0].length; var n = mat.length;
// Cleaning canvas and setting plotting color
ctx.fillStyle="white"; ctx.fillRect(0,0,w,h);
ctx.fillStyle=color;
// MAIN LOOP
for(var i=0; i<m; i++) {
for(var j=0; j<n; j++) {
if(mat[i][j]==1) { ctx.fillRect(i,j,1,1)};
}//fend j
}//fend i
}//func end
</lang>
=PARI/GP Helper Functions=
PARI/GP built-in plotting functions are good only for instant draft math function curves plotting.
Not to mention bad color support and scaling.<br>
In addition, there are no built-in string manipulation functions, except of concatenation.<br>
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