numbers

问题 In java, I am currently in the process of trying to find a way to do mathematical sums by typing in text to a JTextField, putting it into a String, and converting it to an int and solving. The problem is however, I don't want to simply put a number into the string but an actual sum including addition, subtraction etc. Currently it will accept just doing something like, 1 which will go from string and convert to an int, but when I do '1+1' or even just '1+' it throws exceptions everywhere

问题 I'd like to print out all prime numbers from an array with method. I can do it with one int but don't know how to return certain numbers from array. Thanks for help! public static boolean isPrime(int [] tab) { boolean prime = true; for (int i = 3; i <= Math.sqrt(tab[i]); i += 2) if (tab[i] % i == 0) { prime = false; break; } for(int i=0; i<tab.length; i++) if (( tab[i]%2 !=0 && prime && tab[i] > 2) || tab[i] == 2) { return true; } else { return false; } //return prime; } thanks both of you.

问题 In matlab I want to convert this: 12345.6788993442355456789 into a vector [1 2 3 4 5 6 7 8 8 9 9 3 4 4 2 3 5 5 4 5 6 7 8 9] I have found several solutions to convert a integer into a vector using commands like scanf, num2str,... but those don't fit with non-integers, and some solutions have problems with numbers with a large number of decimal places... That kind of conversion is needed because I want to see and use all of the digits of the number. 回答1: What input source are you getting those

问题 My old code was: let comps = split(str, { $0 == "-" || $0 == " " }, maxSplit: Int.max, allowEmptySlices: false) after update of Swift 2 my XCode 7 fix it to: let comps = split(str.characters, { $0 == "-" || $0 == " " }, maxSplit: Int.max, allowEmptySlices: false).map { String($0) } but now I have an error: Cannot invoke 'map' with an argument list of type '((_) -> _)' How to fix it. Link to old answer on Swift 回答1: The order of arguments for split() function messed up for some reason. It

问题 So if we can get past the "should you?" question ... does anyone know how to set the value of an integer in prototype? Number.prototype.add = function(num){ var newVal = this.valueOf() + num; this.valueOf(newVal); return newVal; } var rad = 4001.23; document.write(rad.add(10) + '<br/>' + rad); You'll notice rad.add(10) returns the number contained in the variable "rad" plus 10, but I would really like to change the value of rad from within the prototype add function (something I know this

问题 For example, say: <?php // Grab the ID from URL, e.g. example.com/?p=123 $post_id = $_GET['p']; ?> How do I check if variable $post_id is a number, and a positive integer at that (i.e. 0-9, not a floating point number, fraction, or a negative number)? EDIT: Can't use is_int 'cause $_GET returns a string. Think I need to use intval() or ctype_digit(), with the latter seeming more appropriate. For example: if( ctype_digit( $post_id ) ) { ... } 回答1: To check if a string input is a positive

问题 I'm working on a program that converts numbers to words, but I'm having problems with the toString() method in the Numbers class. All the methods were given to me, so I could implement; therefore, I can't remove any of them... number: 4564 --> four thousand and five hundred and sixty four here's the code Numbers class package numberstowords; import java.util.*; public class Numbers { //array containing single digits words numbers:0-9 private final String[] SINGLE_DIGITS_WORDS; //array

问题 I noticed the following fact with CPython3 and Pypy3, contrasting with the behaviour of both CPython2 and Pypy2: In Python3, it looks like leading zeros when parsing code yield an error except for a very single number wich is 0 . Thus 00 is valid but not 042 . In Python2, leading zeros are allowed for all integers. Thus 00 and 042 are valid. Why did Python change its behaviour between both versions? 回答1: Python 3 standardized how all integer literals (other than base 10) were defined: 0?dddd.

问题 Qestion First : I need to regex to match 111 or 111. or 111.111 (just aritrarty numbers) for a DocumentFilter . I need the user to be able to input 111. with a decimal and nothing afterwards. Can't seem to get it right. All the Regexes I find all match just all decimal numbers i.e. 12343.5565 32.434 32 Like this regex ^[0-9]*(\\.)?[0-9]+$ Problem is, I need the regex for a DocumentFilter so the input can only be numbers with/without a decimal point. But the catch is it also needs to match

问题 A large number can be comma formatted to read more easily into groups of three. E.g. 1050 = 1,050 and 10200 = 10,200 . The sum of each of these groups of three would be: 1050=1,050 gives: 1+50=51 10200=10,200 gives: 10+200=210 I need to search for matches in the sum of the groups of threes. Namely, if I am searching for 1234 , then I am looking for numbers whose sum of threes = 1234 . The smallest match is 235,999 since 235+999=1234 . No other integer less than 235,999 gives a sum of threes