numbers

During some projects I have needed to validate some data and be as certain as possible that it is javascript numerical value that can be used in mathematical operations. jQuery, and some other javascript libraries already include such a function, usually called isNumeric. There is also a post on stackoverflow that has been widely accepted as the answer, the same general routine that the fore mentioned libraries are using. function isNumber(n) { return !isNaN(parseFloat(n)) && isFinite(n); } Being my first post, I was unable to reply in that thread. The issue that I had with the accepted post

I have a data frame (df) and I was wondering how to return the row number(s) for a particular value (2585) in the 4th column (height_chad1) of the same data frame? I've tried: row(mydata_2$height_chad1, 2585) and I get the following error: Error in factor(.Internal(row(dim(x))), labels = labs) : a matrix-like object is required as argument to 'row' Is there an equivalent line of code that works for data frames instead of matrix-like objects? Any help would be appreciated. SethB Use which(mydata_2$height_chad1 == 2585) Short example df <- data.frame(x = c(1,1,2,3,4,5,6,3), y = c(5,4,6,7,8,3,2,4

I'm trying to generate a random number that must have a fixed length of exactly 6 digits. I don't know if JavaScript has given below would ever create a number less than 6 digits? Math.floor((Math.random()*1000000)+1); I found this question and answer on StackOverflow here . But, it's unclear. EDIT: I ran the above code a bunch of times, and Yes, it frequently creates numbers less than 6 digits. Is there a quick/fast way to make sure it's always exactly 6 digits? Cilan console.log( Math.floor(100000 + Math.random() * 900000) ); Will always create a number of 6 digits and it ensures the first

With javascript, how can I do it so when i click a form button it adds 1 to a number? The number it increments could be in a form text field or something. Obviously it'd be on onclick but I'm not sure of the code. Since you gave me nothing to start on, here is a simple example. jsFiddle Example implementation: function incrementValue() { var value = parseInt(document.getElementById('number').value, 10); value = isNaN(value) ? 0 : value; value++; document.getElementById('number').value = value; } Example Html <form> <input type="text" id="number" value="0"/> <input type="button" onclick=

I want to separate the digits of an integer, say 12345, into an array of bytes {1,2,3,4,5}, but I want the most performance effective way to do that, because my program does that millions of times. Any suggestions? Thanks. Jon Skeet How about: public static int[] ConvertToArrayOfDigits(int value) { int size = DetermineDigitCount(value); int[] digits = new int[size]; for (int index = size - 1; index >= 0; index--) { digits[index] = value % 10; value = value / 10; } return digits; } private static int DetermineDigitCount(int x) { // This bit could be optimised with a binary search return x < 10

I know variants of this question have been asked frequently before (see here and here for instance), but this is not an exact duplicate of those. I would like to check if a String is a number, and if so I would like to store it as a double . There are several ways to do this, but all of them seem inappropriate for my purposes. One solution would be to use Double.parseDouble(s) or similarly new BigDecimal(s) . However, those solutions don't work if there are commas present (so "1,234" would cause an exception). I could of course strip out all commas before using these techniques, but that would