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117 lines
4.5 KiB
117 lines
4.5 KiB
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<a href="https://blog.juliobiason.me"><h1>Julio Biason .Me 4.3</h1></a> |
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<p class="lead">Old school dev living in a 2.0 dev world</p> |
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<h1 class="post-title">Things I Learnt The Hard Way - Types Say What You Data Is</h1> |
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2019-06-24 |
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<a href="https://blog.juliobiason.me/tags/books/">#books</a> |
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<a href="https://blog.juliobiason.me/tags/things-i-learnt/">#things i learnt</a> |
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<a href="https://blog.juliobiason.me/tags/types/">#types</a> |
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<p>Memory is just a sequence of bytes; bytes are just numbers from 0 to 255; what |
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those numbers mean is described on the language type system.</p> |
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<span id="continue-reading"></span> |
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<p>For example, in C, a <code>char</code> type of value 65 is most probably the letter "A", |
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which an <code>int</code> of value is 65 is the number 65.</p> |
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<p>Remember this when dealing with your data.</p> |
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<p>And it doesn't matter of your language of choice uses dynamic typing or static |
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typing. The same still applies.</p> |
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<p>One classic example of misusing types is adding booleans. Booleans are either |
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<code>true</code> or <code>false</code>, but because most languages follow C, which doesn't have a |
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boolean type and uses compiler pre-processors to define <code>TRUE</code> as an integer |
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with the value <code>1</code> and <code>FALSE</code> with another integer with the value <code>0</code>. Newer |
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languages were build on top of what older developers knew, and so, a bunch of |
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those languages also assumed using an integer under booleans was a good idea. |
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And even today, with modern languages, people rely on those old methods.</p> |
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<p>Let me repeat that: You're adding booleans and expecting a number -- only |
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because in the old times there wasn't boolean types.</p> |
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<p>No, you're counting the number of elements in the list 'cause that would see |
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the whole list. You're not even filtering the false values over and counting |
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the resulting list size. You're jumping the underlying type to get a bit of |
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performance out.</p> |
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<p>Fortunately, some new languages are using booleans as a complete different |
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type and wouldn't allow this kind of stuff.</p> |
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<< <a href="/books/things-i-learnt/handle-it">If You Know How To Handle It, Handle It</a> |
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<a href="/books/things-i-learnt/use-structures">If Your Data Has a Schema, Use a Structure</a> >> |
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