numbers

问题 In a recent post on http://wtfjs.com/. An author writes following without explanation which happens to be true. 0 === -0 //returns true My understanding about === operator is it returns true if operands point to same object. Also, - operator returns a reference to negative value of operand. With this rule, 0 and -0 should not be the same. So, why is 0 === -0 ? 回答1: In fact, 0 and -0 are not the same even at the bit level. However, there is a special case implemented for +/-0 so they compare

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 6 years ago . I'm trying to understand the range of data types. For non-floating point numbers it's easy enough, but then for float and double the ranges are listed as: float: 3.4E +/- 38 (7 digits) double: 1.7E +/- 308 (15

问题 Number.prototype.isInteger = Number.prototype.isInteger || function(x) { return (x ^ 0) === x; } console.log(Number.isInteger(1)); will throw error in IE10 browser 回答1: Apparently, IE treats DOM objects and Javascript objects separately, and you can't extend the DOM objects using Object.prototype. IE doesn't let you use a prototype that is not native.. You'll have to make a separate function (global if you want) as function isInteger(num) { return (num ^ 0) === num; } console.log(isInteger(1)

问题 This question already has answers here : What is JavaScript's highest integer value that a number can go to without losing precision? (21 answers) Closed 3 years ago . console.log(10209761399365907); Why does this code output a number greater by one (10209761399365908 instead of 10209761399365907)? This is happening only for this specific number. For instance with 10155071933693662 I get the correct value (10155071933693662). Is there something I need to know about that specific number? The

问题 I am using JSON.stringify() on html <input> s to send through a websocket like so: JSON.stringify({ numberValue: $('#numberValue').val() }) but it encodes $('#numberValue').val() as a String . How can it be encoded as a Number ? 回答1: Convert it to an integer first. JSON.stringify({ numberValue: parseInt($('#numberValue').val(), 10); }) 回答2: You can parse the string: JSON.stringify({ numberValue: parseInt($('#numberValue').val(), 10); }) The parseInt() function parses a string and returns an

问题 I was wondering if there is a straightforward way to display line numbers with StyledText text field - even if lines are wrapped. I'm using it in my application and if content gets to big, some line numbers would be nice. Thank you. 回答1: The key is org.eclipse.swt.custom.Bullet . It's basically a symbol (or in our case a number) you can add to the beginning of a line. //text is your StyledText text.addLineStyleListener(new LineStyleListener() { public void lineGetStyle(LineStyleEvent e) { /

问题 I need to compute the integral of the following function within ranges that start as low as -150 : import numpy as np from scipy.special import ndtr def my_func(x): return np.exp(x ** 2) * 2 * ndtr(x * np.sqrt(2)) The problem is that this part of the function np.exp(x ** 2) tends toward infinity -- I get inf for values of x less than approximately -26 . And this part of the function 2 * ndtr(x * np.sqrt(2)) which is equivalent to from scipy.special import erf 1 + erf(x) tends toward 0. So, a

问题 How to validate using Javascript an input tag of type text in an html form that the content of it will be one of the following:- Arabic or English Characters ONLY -OR- Arabic and English Characters ONLY -OR- Arabic characters only -OR- English Characters only -OR- Number only -OR- Arabic Characters and Number only -OR- English Characters and Number only -OR- Arabic or Number ONLY -OR- English Characters or Number ONLY -OR- Arabic or English Characters or Number ONLY -OR- Phone Number -OR-

问题 Let's say I have a table in Oracle 12c with columns: create table t1 ( a number (5,0), b varchar (5,0) d ... e ... ); Then I insert 100,000,000 records in both columns which have the same values - e.g. 20151 and '20152' ... (for a first record) 20152 and '20152' ... (for a second record) 20153 and '20153' ... (for a third record) ... Then I add index 1 on column 'a' and index 2 on column 'b'. Question is - would the query perform equally fast when executing against column 'a' as on column 'b'

问题 I have a list of objects in a table-view i would like to sort properly. Amongst other things, my objects contain a name-field. This name field can also contain numbers, so for example: Chairman Seat 1 Seat 2 Seat 3 Seat 11 Seat 12 Seat 23 Secretary This is however sorted like this: Chairman Seat 1 Seat 11 Seat 12 Seat 2 Seat 23 Seat 3 Secretary This doesn't seem like a natural way of sorting my list when sorting by name. Now i'm using the ng-repeat like this: seat in seats | orderBy