in javascript how randomly generate number between -0.5 , 0.5? following seems give positive numbers, , no negative numbers.
math.random(-0.15, 0.15)
quoting mdn on math.random,
the
math.random()function returns floating-point, pseudo-random number in range [0, 1) is, 0 (inclusive) not including 1 (exclusive)
so, generate random numbers between 0 , 1 , subtract 0.5 it.
math.random() - 0.5 note: math.random() doesn't expect parameters. so, cannot specify range.
if want generate random numbers between range, use example snippets in mdn,
// returns random number between min (inclusive) , max (exclusive) function getrandomarbitrary(min, max) { return math.random() * (max - min) + min; } demo range
function getrandomarbitrary(min, max) { return math.random() * (max - min) + min; } function appendtoresult(value) { document.getelementbyid("result").innerhtml += value + "<br />"; } document.getelementbyid("result").innerhtml = ""; (var = 0; < 10; += 1) { appendtoresult(getrandomarbitrary(-0.35, 0.35)); }<pre id="result" />this works because, expression
math.random() * (max - min) + min will evaluated in following manner. first,
math.random() will evaluated random number in range 0 , 1 , then
math.random() * (max - min) it multiplied difference between max , min value. in case, lets max 0.35 , min -0.35. so, max - min becomes 0.7. so, math.random() * (max - min) gives number in range 0 , 0.7 (because if math.random() produces 1, when multiply 0.7, result become 0.7). then, do
math.random() * (max - min) + min so, case, becomes,
math.random() * (0.35 - (-0.35)) + (-0.35) (math.random() * 0.7) - 0.35 so, if (math.random() * 0.7) generates value greater 0.35, since subtract 0.35 it, becomes number between 0 , 0.35. if (math.random() * 0.7) generates value lesser 0.35, since subtract 0.35 it, becomes number between -0.35 , 0.
Comments
Post a Comment