x307F;&#x3061;&#x304C;&#x3042;&#x308A;&#x307E;&#x3059;&#x3002;&#x90E8;&#x5206;&#x95A2;&#x6570;&#x3068;&#x5165;&#x529B;&#x304C;&#x4EFB;&#x610F;&#x306E;&#x30D5;&#x30A3;&#x30FC;&#x30EB;&#x30C9;&#x3067;&#x5F79;&#x7ACB;&#x3061;&#x307E;&#x3059;&#x3002;</p>
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## Partial Functions
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<h2 id="&#x90E8;&#x5206;&#x95A2;&#x6570;">&#x90E8;&#x5206;&#x95A2;&#x6570;</h2>
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Sometimes you want a function that gives an answer for some inputs, but not others. Many people run into this with [`String.toFloat`][toFloat] whe