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Abstract

er">17</span>]</pre></div><blockquote id="c020"><p>Compact Map()</p></blockquote><p id="b1c2"><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.</p><div id="9cf9"><pre><span class="hljs-keyword">extension</span> <span class="hljs-title class_">Array</span> { <span class="hljs-keyword">func</span> <span class="hljs-title function_">compactMap</span><<span class="hljs-type">T</span>>(<span class="hljs-keyword">_</span> <span class="hljs-params">transforms</span>: (<span class="hljs-type">Element</span>) -> <span class="hljs-type">T</span>?) -> [<span class="hljs-type">T</span>] { <span class="hljs-keyword">var</span> result <span class="hljs-operator">=</span> <span class="hljs-type">T</span> <span class="hljs-keyword">for</span> element <span class="hljs-keyword">in</span> <span class="hljs-keyword">self</span> { <span class="hljs-keyword">if</span> <span class="hljs-keyword">let</span> element <span class="hljs-operator">=</span> element { result.append(transform(element)) } } <span class="hljs-keyword">return</span> result } }</pre></div><p id="fe9c">Here the only change from <code>Map</code> and <code>Compact Map</code> is avoiding the nil value with a condition.</p><p id="3b42">In the above code</p><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"><p>How to consume it?</p></blockquote><div id="41f1"><pre><span class="hljs-keyword">let</span> mapArray <span class="hljs-operator">=</span> [<span class="hljs-number">23</span>, <span class="hljs-number">43</span>, <span class="hljs-number">56</span>, <span class="hljs-literal">nil</span>, <span class="hljs-number">75</span>, <span class="hljs-number">9</span>, <span class="hljs-number">14</span>] <span class="hljs-keyword">let</span> result<span class="hljs-operator">=</span> mapArray.compactMap { <span class="hljs-variable">$0</span> } <span class="hljs-built_in">debugPrint</span>(result) output: [<span class="hljs-number">23</span>, <span class="hljs-number">43</span>, <span class="hljs-number">56</span>, <span class="hljs-number">75</span>, <span class="hljs-number">9</span>, <span class="hljs-number">14</span>]</pre></div><blockquote id="854c"><p>Flat Map()</p></blockquote><p id="b656">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</p><div id="6431"><pre><span class="hljs-keyword">extension</span> <span class="hljs-title class_">Array</span> { <span class="hljs-keyword">func</span> <span class="hljs-title function_">flatMap</span><<span class="hljs-type">T</span>>(<span class="hljs-keyword">_</span> <span class="hljs-params">transform</span>: (<span class="hljs-type">Element</span>) -> [<span class="hljs-type">T</span>]) -> [<span class="hljs-type">T</span>] { <span class="hljs-keyword">var</span> result <span class="hljs-operator">=</span> <span class="hljs-type">T</span> <span class="hljs-keyword">for</span> element <span class="hljs-keyword">in</span> <span class="hljs-keyword">self</span> { result.append(contentsOf: transform(element)) } <span class="hljs-keyword">return</span> result } }</pre></div><p id="75fa">In the above code</p><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"><p>How to consume it?</p></blockquote><div id="117f"><pre><span class="hljs-keyword">let</span> arrayOfArrays <span class="hljs-operator">=</span> [[<span class="hljs-number">1</span>, <span class="hljs-number">2</span>, <span class="hljs-number">3</span>], [<span class="hljs-number">4</span>, <span class="hljs-number">5</span>, <span class="hljs-number">6</span>], [<span class="hljs-number">7</span>, <span class="hljs-number">8</span>, <span class="hljs-number">9</span>]] <span class="hljs-keyword">let</span> transformedArray <span class="hljs-operator">=</span> arrayOfArrays.flatMap { <span class="hljs-variable">$0</span> } <span class="hljs-built_in">print</span>(transformedArray) output: [<span class="hljs-number">1</span>, <span class="hljs-number">2</span>, <span class="hljs-number">3</span>, <span class="hljs-number">4</span>, <span class="hljs-number">5</span>, <span class="hljs-number">6</span>, <span class="hljs-number">7</span>, <span class="hljs-number">8</span>, <span class="hljs-number">9</span>]</pre></div><h1 id="3bda">Conclusion</h1><p id="057c">There are plenty of other use cases for higher-order functions. This is a gist of what we have discovered today:</p><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><p id="0a10">Thank you for your time and attention! 👏👏👏</p><p id="33e6">Do clap👏 if you like this and comment your suggestions!!! <i>Happy coding</i>!!!</p><blockquote id="1e0c"><p>Source Code: <a href="https://github.com/Vikassingamsetty/HigherOrderFunctions.git">GitHub</a></p></blockquote></article></body>

Github

GitHub Error Message — Permission denied (public key)

Permission denied (public key) fatal: Could not read from remote repository Show git Error.

Github Error Message — permission denied (public key)

In This Post, I'm Told and Help you. How to Resolve this Error Permission denied (public key).

Why Show Error?

Mostly commonly show an Error when we use after a long time Bash || Git so in that case, we offer an Error. Handle that Error. Create New SSH KEY for Github.

Look Like

Permission denied (public key)

Let's Start It?

  1. Open Bash
  2. Run Command
  3. Go to Github

Open Bash

Desktop Home > Click Right key On Mouse( Laptop pad Right Key). After the open menu, selects Git bash here. Then open bash Terminal on your laptop || desktop.

Open Bash

Run Command

Go To your bash terminal on your laptop after copying past or writing a new terminal command to generate an SSH key for your Github.

Command Paste your bash terminal

ssh-keygen  // copy that past in bash cmd terminal
ssh-agent // that command tell you active connection list and some SSH key information
ssh-agent tell you active connection
Download SSH Key For GitHub

Go to Github

First, open GitHub on your browser and click the setting tab. After scrolling down, select SSH and GPG key tab and click after opening the new ssh key page on Github. It gives a simple Tittle or project name; past your ssh key, click the add ssh key button.

Note

Copy only the .pub Extention File and paste it on Github key tab.

Add SSH key On Github

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Conclusion

I hope you understand how to resolve that Error Message — Permission denied (public key). Suppose there are Any queries, mistakes, and Suggestions. Then, please, tell me in the comment box.

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