How can I do this using regex, replacing every string with ! wrapped in function:
Examples:
3!=>fact(3)2.321!=>fact(2.321)(3.2+1)!=>fact(3.2+1)(sqrt(2)+2/2^2)!=>fact(sqrt(2)+2/2^2)
5 Answers
Given your examples, you don't need a regex at all:
var s = "3!"; //for example
if (s[s.length-1] === "!")
s = "fact(" + s.substr(0, s.length-1) + ")";
Not doubling the parentheses for the last case just requires another test:
var s = "(sqrt(2)+2/2^2)!"; //for example
if (s[s.length-1] === "!") {
if(s.length > 1 && s[0] === "(" && s[s.length-2] === ")")
s = "fact" + s.substr(0, s.length-1);
else
s = "fact(" + s.substr(0, s.length-1) + ")";
}
Comments
My own answer i just found out was:
Number.prototype.fact = function(n) {return fact(this,2)}
str = str.replace(/[\d|\d.\d]+/g, function(n) {return "(" + n + ")"}).replace(/\!/g, ".fact()")
But I'll see if the other answers might be much better, think they are
1 Comment
Alan Moore
[\d|\d.\d] isn't doing what you probably think it is. It's a character class that matches one character at a time: a digit, a pipe (|), or a period (\.). This is probably what you're looking for: \d+(?:\.\d+)?Here is as the op requested; using regexp:
"3*(2+1)!".replace(/([1-9\.\(\)\*\+\^\-]+)/igm,"fact($1)");
You might end up with double parentheses:
"(2+1)!".replace(/([1-9\.\(\)\*\+\^\-]+)/igm,"fact($1)");
Comments
"(sqrt(2)+2/2^2)!".replace(/(.*)!/g, "fact($1)");
(.*)!
Match the regular expression below and capture its match into backreference number 1
(.*)- Match any single character that is not a line break character
. - Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
*
- Match any single character that is not a line break character
- Match the character “!” literally
!
1 Comment
HMR
I assumed there might be other characters in the string that do not need to be put in fact(...)
var testArr = [];
testArr.push("3!");
testArr.push("2.321!");
testArr.push("(3.2+1)!");
testArr.push("(sqrt(2)+2/2^2)!");
//Have some fun with the name. Why not?
function ohIsThatAFact(str) {
if (str.slice(-1)==="!") {
str = str.replace("!","");
if(str[0]==="(" && str.slice(-1)===")")
str = "fact"+str;
else
str = "fact("+str+")";
}
return str;
}
for (var i = 0; i < testArr.length; i++) {
var testCase = ohIsThatAFact(testArr[i]);
document.write(testCase + "<br />");
}
replacemethod