<h2 id="heading-url">URL</h2>
<a target="_blank" href="https://leetcode.com/problems/number-of-senior-citizens/description/?envType=daily-question&amp;envId=2024-08-01">Number of Senior Citizens - LeetCode</a>
<h2 id="heading-code">Code</h2>
<a target="_blank" href="https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202408/number_of_senior_citizens/main.fsx">https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202408/number_of_senior_citizens/main.fsx</a>
<pre><code class="lang-fsharp">let countSeniors (details: string list) : int =
 details
 |&gt; List.filter (fun detail -&gt; detail.[11] &gt;= '6' &amp;&amp; detail.[12] &gt;= '1')
 |&gt; List.length

// 2
countSeniors [ "7868190130M7522"; "5303914400F9211"; "9273338290F4010" ]

// 0
countSeniors [ "1313579440F2036"; "2921522980M5644" ]
</code></pre>

## URL

[Number of Senior Citizens - LeetCode](https://leetcode.com/problems/number-of-senior-citizens/description/?envType=daily-question&envId=2024-08-01)

## Code

[https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202408/number\_of\_senior\_citizens/main.fsx](https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202408/number_of_senior_citizens/main.fsx)

```fsharp
let countSeniors (details: string list) : int =
    details
    |> List.filter (fun detail -> detail.[11] >= '6' && detail.[12] >= '1')
    |> List.length

// 2
countSeniors [ "7868190130M7522"; "5303914400F9211"; "9273338290F4010" ]

// 0
countSeniors [ "1313579440F2036"; "2921522980M5644" ]
```

LeetCode 2678. Number of Senior Citizens in F#

URL

Code