arrays - Read For Learn

Difference between map and collect in Ruby?

There’s no difference, in fact map is implemented in C as rb_ary_collect and enum_collect (eg. there is a difference between map on an array and on any other enum, but no difference between map and collect). Why do both map and collect exist in Ruby? The map function has many naming conventions in different languages. Wikipedia provides an overview: The map function originated in functional programming languages but is today supported (or may be … Read more

How to print the full NumPy array, without truncation?

Use numpy.set_printoptions:

How do I concatenate two arrays in C#?

PHP array printing using a loop

How to allocate array of pointers for strings by malloc in C?

As I can understand from your assignment statement in while loop I think you need array of strings instead: Note: By doing = in while loop as below: you are just assigning address of string (its not deep copy), but because you are also writing “only address of strings” so I think this is what you wants. … Read more

How to sort an array of integers correctly

By default, the sort method sorts elements alphabetically. To sort numerically just add a new method which handles numeric sorts (sortNumber, shown below) – Documentation: Mozilla Array.prototype.sort() recommends this compare function for arrays that don’t contain Infinity or NaN. (Because Infinity – Infinity is NaN, not 0). Also examples of sorting objects by key.

How to increase the size of an array in Java?

Instead of using an array, use an implementation of java.util.List such as ArrayList. An ArrayList has an array backend which holds values in a list, but the array size is automatically handles by the list. You can also convert the list into an array using list.toArray(new String[list.size()]) and so forth for other element types.

JavaScript array to CSV

The cited answer was wrong. You had to change to As to why the cited answer was wrong (funny it has been accepted!): index, the second parameter of the forEach callback function, is the index in the looped-upon array, and it makes no sense to compare this to the size of infoArray, which is an … Read more

inverting image in Python with OpenCV

You almost did it. You were tricked by the fact that abs(imagem-255) will give a wrong result since your dtype is an unsigned integer. You have to do (255-imagem) in order to keep the integers unsigned: You can also invert the image using the bitwise_not function of OpenCV:

How to Sort a Multi-dimensional Array by Value

Try a usort. If you are still on PHP 5.2 or earlier, you’ll have to define a sorting function first: Starting in PHP 5.3, you can use an anonymous function: And finally with PHP 7 you can use the spaceship operator: To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first … Read more

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