infinity

How to express infinity in Ruby?

由 ◇◆丶佛笑我妖孽 提交于 2019-11-27 05:41:26
问题 Is there a keyword to express Infinity in Ruby? 回答1: If you use ruby 1.9.2, you can use : >> Float::INFINITY #=> Infinity >> 3 < Float::INFINITY #=> true Or you can create your own constant using the following*: I've checked that in Ruby 1.8.6, 1.8.7, and 1.9.2 you have Float.infinite?. PositiveInfinity = +1.0/0.0 => Infinity NegativeInfinity = -1.0/0.0 => -Infinity CompleteInfinity = NegativeInfinity..PositiveInfinity => -Infinity..Infinity *I've verified this in Ruby 1.8.6 and 1.9.2 回答2: No

How do I check if a number evaluates to infinity?

由 依然范特西╮ 提交于 2019-11-27 05:17:46
问题 I have a series of Javascript calculations that (only under IE) show Infinity depending on user choices. How does one stop the word Infinity appearing and for example, show 0.0 instead? 回答1: if (result == Number.POSITIVE_INFINITY || result == Number.NEGATIVE_INFINITY) { // ... } You could possibly use the isFinite function instead, depending on how you want to treat NaN . isFinite returns false if your number is POSITIVE_INFINITY , NEGATIVE_INFINITY or NaN . if (isFinite(result)) { // ... }

In JavaScript, why does zero divided by zero return NaN, but any other divided by zero return Infinity?

由 拟墨画扇 提交于 2019-11-27 04:44:11
It seems to me that the code console.log(1 / 0) should return NaN , but instead it returns Infinity . However this code: console.log(0 / 0) does return NaN . Can someone help me to understand the reasoning for this functionality? Not only does it seem to be inconsistent, it also seems to be wrong, in the case of x / 0 where x !== 0 Because that's how floating-point is defined (more generally than just Javascript). See for example: http://en.wikipedia.org/wiki/Floating-point#Infinities http://en.wikipedia.org/wiki/NaN#Creation Crudely speaking, you could think of 1/0 as the limit of 1/x as x

Why does node not evaluate Math.tan(Math.PI/2) to Infinity but Chrome V8 does?

由 爷，独闯天下 提交于 2019-11-27 02:36:47
问题 When running this in a node command-line interface: > Math.tan(Math.PI/2) 16331778728383844 But in Chrome: > Math.tan(Math.PI/2) Infinity Aren't both using the same V8 engine? Node's result is not even equal to the maximum "integer" value in JavaScript. 回答1: If you look at the v8 implementation of the Math object, you see: function MathTan(x) { return MathSin(x) / MathCos(x); } Indeed, Math.cos(Math.PI/2) returns an unusual value in Node as well (in fact, the reciprocal of your unusual Math

How do I create or test for NaN or infinity in Perl?

由 好久不见. 提交于 2019-11-26 21:28:21
问题 How do I create or test for NaN or infinite values in Perl? 回答1: print "Is NaN\n" if $a eq 'nan'; print "Is Inf\n" if $a eq 'inf' or $a eq '-inf'; EDIT : Fixed for negative infinity. 回答2: Here's a fairly reliable way: my $inf = 9**9**9; my $neginf = -9**9**9; my $nan = -sin(9**9**9); sub isinf { $_[0]==9**9**9 || $_[0]==-9**9**9 } sub isnan { ! defined( $_[0] <=> 9**9**9 ) } # useful for detecting negative zero sub signbit { substr( sprintf( '%g', $_[0] ), 0, 1 ) eq '-' } for my $num ( $inf,

Adding to Number.MAX_VALUE

由 妖精的绣舞 提交于 2019-11-26 21:05:14
The answer to this question may be painfully obvious but I can't find it in the Mozilla docs nor on Google from a cursory search. If you have some code like this Number.MAX_VALUE + 1; // Infinity, right? Number.MIN_VALUE - 1; // -Infinity, right? Then I would expect adding anything to Number.MAX_VALUE would push it over to Infinity . The result is just Number.MAX_VALUE spat right back at me. However, when playing around in the Chrome JS console, I noticed that it didn't actually become Infinity until I added/subtracted enough: Number.MAX_VALUE + Math.pow(100,1000); // now we hit Infinity

How do you get VB6 to initialize doubles with +infinity, -infinity and NaN?

由 ╄→尐↘猪︶ㄣ 提交于 2019-11-26 21:03:35
问题 VB6 doesn't appear to make it that easy to store +infinity, -infinity and NaN into double vars. It would help if it could so that I could do comparisons with those values in the context of complex numbers. How? 回答1: A few different things. As you can see from Pax's example, you really just need to look up the IEEE 754 standard and then plug your bytes into the right places. The only caution I would give you is that MicroSoft has deprecated RtlMoveMemory due to it's potential for creating

How to generate NaN, -Infinity and +Infinity in ANSI C?

由 旧巷老猫 提交于 2019-11-26 19:58:59
问题 I use ANSI C89 (not C++), and I want to generate NaN, -Infinity and +Infinity. Is there any standard way (eg. standard macro)? Or is there any platform and compiler independent way to generate these numbers? float f = 0.0 / 0.0; // Is f ALWAYS in any platform is NaN? 回答1: There is in C99, but not in previous standards AFAIK. In C99, you'll have NAN and INFINITY macros. From "Mathematics <math.h> " (§7.12) section The macro INFINITY expands to a constant expression of type float representing

How can I represent an infinite number in Python?

由 此生再无相见时 提交于 2019-11-26 14:58:23
问题 How can I represent an infinite number in python? No matter which number you enter in the program, no number should be greater than this representation of infinity. 回答1: In Python, you can do: test = float("inf") In Python 3.5, you can do: import math test = math.inf And then: test > 1 test > 10000 test > x Will always be true. Unless of course, as pointed out, x is also infinity or "nan" ("not a number"). Additionally (Python 2.x ONLY), in a comparison to Ellipsis , float(inf) is lesser, e.g

JSON.stringify converting Infinity to null

由 我怕爱的太早我们不能终老 提交于 2019-11-26 14:28:32
问题 I have JavaScript Object say: var a = {b: Infinity, c: 10}; When I do var b = JSON.stringify(a); it returns the following b = "{"b":null, "c":10}"; How is the JSON.stringify converts the object to strings? I tried MDN Solution. function censor(key, value) { if (value == Infinity) { return "Infinity"; } return value; } var b = JSON.stringify(a, censor); But in this case I have to return the string "Infinity" not Infinity . If I return Infinity it again converts Infinity to null. How do I solve
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