Mapping Values Are Not Allowed Here

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Abstract

er">17]</pre></div><blockquote id="c020">Compact Map()</blockquote><code>compactMap</code> function is similar to <code>map</code>, but it also includes an additional step, it filters out any <code>nil</code> values that result from applying the transformation closure. This is particularly useful when you have an array of optional values and you want to transform them while simultaneously filtering out the <code>nil</code> elements.<div id="9cf9"><pre>extension Array { func compactMap<T>(_ transforms: (Element) -> T?) -> [T] { var result = T for element in self { if let element = element { result.append(transform(element)) } } return result } }</pre></div>Here the only change from <code>Map</code> and <code>Compact Map</code> is avoiding the nil value with a condition.In the above code<ul><li>It takes a closure <code>transform</code> as an argument, which specifies how each element should be transformed.</li><li>Inside <code>compactMap</code>, a new array <code>result</code> is created to store the transformed non-nil elements.</li><li>It then iterates over each element of the original array (<code>self</code>), applies the transformation closure to each element, and checks if the result is non-nil.</li><li>If the result is non-nil, it appends the transformed element to the <code>result</code> array.</li><li>Finally, it returns the <code>result</code> array containing all the non-nil transformed elements.</li></ul><blockquote id="9909">How to consume it?</blockquote><div id="41f1"><pre>let mapArray = [23, 43, 56, nil, 75, 9, 14] let result= mapArray.compactMap { $0 } debugPrint(result) output: [23, 43, 56, 75, 9, 14]</pre></div><blockquote id="854c">Flat Map()</blockquote>FlatMap is typically the same as <code>map</code> does, only difference is that it always return flatten array joining all elements. Typically used to collect specific data in n

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ested array, dictionary or set<div id="6431"><pre>extension Array { func flatMap<T>(_ transform: (Element) -> [T]) -> [T] { var result = T for element in self { result.append(contentsOf: transform(element)) } return result } }</pre></div>In the above code<ul><li>It takes a closure <code>transform</code> as an argument, which specifies how each element should be transformed into a sequence.</li><li>Inside <code>flatMap</code>, a new array <code>result</code> is created to store the flattened elements.</li><li>It then iterates over each element of the original array (<code>self</code>), applies the transformation closure to each element, and concatenates the resulting sequences into the <code>result</code> array.</li><li><code>append(contentsOf: )</code> will add the elements of a sequence to the end of the array.</li><li>Finally, it returns the <code>result</code> array containing all the flattened elements.</li></ul><blockquote id="2285">How to consume it?</blockquote><div id="117f"><pre>let arrayOfArrays = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] let transformedArray = arrayOfArrays.flatMap { $0 } print(transformedArray) output: [1, 2, 3, 4, 5, 6, 7, 8, 9]</pre></div><h1 id="3bda">Conclusion</h1>There are plenty of other use cases for higher-order functions. This is a gist of what we have discovered today:<ul><li>If you need to simply transform a value to another value, then use <code>map</code>.</li><li>If you need to remove nil values, then use <code>compactMap</code>.</li><li>If you need to flatten your result one level down, then use <code>flatMap</code>.</li></ul>Thank you for your time and attention! 👏👏👏Do clap👏 if you like this and comment your suggestions!!! Happy coding!!!<blockquote id="1e0c">Source Code: <a href="https://github.com/Vikassingamsetty/HigherOrderFunctions.git">GitHub</a></blockquote></article></body>

Mapping Values Are Not Allowed Here — missing quote

Fn::Join results in missing quotes when used with Sub