34 lines
6.4 KiB
Plaintext
34 lines
6.4 KiB
Plaintext
-->
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<span style="color: #008080;">constant</span> <span style="color: #000000;">word</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"the"</span><span style="color: #0000FF;">,</span> <span style="color: #000080;font-style:italic;">-- (also try this with "th"/"he")</span>
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<span style="color: #000000;">sentence</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"the last thing the man said was the"</span>
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<span style="color: #000080;font-style:italic;">-- sentence = "thelastthingthemansaidwasthe" -- (practically the same results)
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-- A common, but potentially inefficient idiom for checking for a substring at the start is:</span>
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<span style="color: #008080;">if</span> <span style="color: #7060A8;">match</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span>
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<span style="color: #0000FF;">?</span><span style="color: #008000;">"yes(1)"</span>
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<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
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<span style="color: #000080;font-style:italic;">-- A more efficient method is to test the appropriate slice</span>
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<span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">)>=</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">)</span>
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<span style="color: #008080;">and</span> <span style="color: #000000;">sentence</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">)]=</span><span style="color: #000000;">word</span> <span style="color: #008080;">then</span>
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<span style="color: #0000FF;">?</span><span style="color: #008000;">"yes(2)"</span>
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<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
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<span style="color: #000080;font-style:italic;">-- Which is almost identical to checking for a word at the end</span>
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<span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">)>=</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">)</span>
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<span style="color: #008080;">and</span> <span style="color: #000000;">sentence</span><span style="color: #0000FF;">[-</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">)..-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]=</span><span style="color: #000000;">word</span> <span style="color: #008080;">then</span>
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<span style="color: #0000FF;">?</span><span style="color: #008000;">"yes(3)"</span>
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<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
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<span style="color: #000080;font-style:italic;">-- Or sometimes you will see this, a tiny bit more efficient:</span>
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<span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">)>=</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">)</span>
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<span style="color: #008080;">and</span> <span style="color: #7060A8;">match</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">)-</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">)+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
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<span style="color: #0000FF;">?</span><span style="color: #008000;">"yes(4)"</span>
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<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
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<span style="color: #000080;font-style:italic;">-- Finding all occurences is a snap:</span>
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<span style="color: #004080;">integer</span> <span style="color: #000000;">r</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">match</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">)</span>
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<span style="color: #008080;">while</span> <span style="color: #000000;">r</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">do</span>
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<span style="color: #0000FF;">?</span><span style="color: #000000;">r</span>
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<span style="color: #000000;">r</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">match</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">,</span><span style="color: #000000;">r</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
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<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
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<span style="color: #000080;font-style:italic;">-- or equivalently:</span>
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<span style="color: #0000FF;">?</span><span style="color: #7060A8;">match_all</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sentence</span><span style="color: #0000FF;">)</span>
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<!--
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