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Order two numerical lists: Difference between revisions
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The function should accept two lists as arguments and return <code>true</code> if the first list should be ordered before the second, and <code>false</code> otherwise.
The order is determined by [[wp:Lexicographical order#Ordering of sequences of various lengths|lexicographic order]]: Comparing the first element of each list.
If the first elements are equal, then the second elements should be compared, and so on, until one of the list has no more elements.
If the first list runs out of elements the result is <code>true</code>.
If the second list or both run out of elements the result is <code>false</code>.
=={{header|ACL2}}==
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end Order;
</lang>
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<pre>
TRUE
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}
</lang>
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<pre>
list1<list2
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IF list1(i%) > list2(i%) THEN = FALSE
= l1% < l2%</lang>
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<pre>
list1<list2
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=={{header|Bracmat}}==
When evaluating a sum or a product, Bracmat creates an expression with a canonical order, which happens to be compatible with the order defined in this task.
In a pattern, only a sum or product on the left hand side (lhs) of the match (<code>:</code>) operator is evaluated.
In the solution below we match a composition of the two function arguments into a sum of two terms with itself.
If the match expression succeeds, the lhs must already have been in canonical order before evaluation, which means that the first argument is smaller than the second argument.
In that case the function outputs FALSE.
Notice that if the arguments are the same, evaluation of the sum produces the product of one of the terms and a factor two. This complicates the pattern a bit.
<lang bracmat>( 1 2 3 4 5:?List1
& 1 2 1 5 2 2:?List2
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& gt$(!List6,!List7)
);</lang>
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<pre>TRUE
TRUE
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return b
}</lang>
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<pre>
order [0] before [] : false
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)
#first < #second</lang>
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<pre>false
true</pre>
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print :list1 = :list2</lang>
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<lang logo>true
false
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end</lang>
<pre>
{10, 7, 4, 9, 10, 3, 5, 5, 5, 5} > {7, 4, 6, 4, 3, 5, 10}
{5, 7} <= {6, 3, 7, 7, 7, 1}
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{4, 3, 4, 6, 3, 6, 7, 2, 2, 5} > {3, 10, 6, 8, 1}
{1, 5, 1, 5, 4} > {1, 3, 5, 3, 2, 10, 1}
</pre>
=={{header|Mathematica}}==
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echo([1,2,1,3,2] < [1,2,0,4,4,0,0,0])</lang>
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<pre>false</pre>
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EndIf
</lang>
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<pre>False
False
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if wx<wy then return 'true'
return 'false'</lang>
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<pre>
[1 2 1 5 2] < [1 2 1 5 2 2]
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ENDLOOP
</lang>
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<pre style='height:30ex;overflow:scroll'>
false: 1'2'5'6'7 < 1'2'1'3'2
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(car.a < car.b)</lang>
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<pre>(< '(1 2 3) '(1 2 4))
=> 4
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