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I want to call .map on only the first X elements of an array. How do I do this?
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map() calls a function once for each element in an array. map() does not execute the function for empty elements. map() does not change the original array.
To map() only a portion of an array in React: Call the slice() method on the array to get a portion of the array. Call the map() method on the portion of the array. Iterate over the portion of the array.
Using reset() function: The reset() function is used to move the array's internal pointer to the first element. Example: This example illustrates the use of the reset() function that helps to move any array's internal pointer to the first element of that array.
The first and last elements are accessed using an index and the first value is accessed using index 0 and the last element can be accessed through length property which has one more value than the highest array index. The array length property in JavaScript is used to set or return the number of elements in an array.
In ruby 1.9
array.first(X).map{|e| ...}
In ruby 1.8
array[0, X].map{|e| ...}
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