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Rails: Is there a rails trick to adding commas to large numbers?

... either , or . for decimal digits, even if you specify it as argument). It allocates thousands of objects (so its performance patterns are complex and hard to profile). Consider just using regexps if you don't need to support different ways to format numbers depending on locale. ...
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Create an array with same element repeated multiple times

... It's much more efficient to allocate all of the entries up front, with arr = new Array(len);, then assign to them by index in the loop, i.e. arr[i] = value;. That way you only pay O(n) rather than having to keep reallocating the array as it grows. In ...
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Open and write data to text file using Bash?

...lly holds a lot. Usually the max number of file descriptors the kernel can allocate can be found in /proc/sys/file-max or /proc/sys/fs/file-max but using any fd above 9 is dangerous as it could conflict with fd's used by the shell internally. So don't bother and only use fd's 0-9. If you need more t...
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Is there a way to instantiate a class by name in Java?

...object (to be the most precise, creating a new object involves both memory allocation and object construction). So the nearest equivalent to the previous example is to say: import java.lang.reflect.*; public class constructor2 { public constructor2() { } public construc...
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How to sort in mongoose?

...e query. The Model.find() implementation (at this version) does a sliding allocation of properties to handle optional params (which is what confused me!): Model.find = function find (conditions, fields, options, callback) { if ('function' == typeof conditions) { callback = conditions; co...
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Draw a perfect circle from user's touch

...Hough Transform is a voting scheme. A two dimensional array of integers is allocated and all elements are set to zero. Each element corresponds to a single pixel in the image being analyzed. This array is referred to as the accumulator array since each element will accumulate information, votes, ind...
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String length in bytes in JavaScript

... If you only need the length, it might be overkill to allocate a new string, do the actual conversion, take the length, and then discard the string. See my answer above for a function that just computes the length in an efficient manner. – lovasoa ...
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How to determine if an NSDate is today?

...me for the second date and compare: NSCalendar * gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; NSDateComponents * components = [gregorian components: (NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit) ...
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Getting an object from an NSSet

...ck for whether it's in the NSSet) with: MyObject *testObject = [[MyObject alloc] init]; testObject.objectID = 5; // for example. // I presume your object has more properties which you don't need to set here // because it's objectID that defines uniqueness (see isEqual: above) MyObject *existin...
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Passing an array by reference

How does passing a statically allocated array by reference work? 5 Answers 5 ...