blocks|key|2820457|text|诀窍是对索引号列表进行排序，然后选择第一个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2820458|my+$ix+=+(sort+{+$array[$a])+<=>+$array[$b]+}+grep+{+$array[$_]+>=+0+}+0..$#array)[0];|code-block|syntax|javascript|2820459|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The trick is to sort a list of index numbers, then pick the first one:

<pre><code>my $ix = (sort { $array[$a]) &lt;=&gt; $array[$b] } grep { $array[$_] &gt;= 0 } 0..$#array)[0];
</code></pre>

blocks|key|89053|text|你想要对数(O(N))，而不是sort+(O(N+reduce+N))！|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|89054|use+List::Util+qw(+reduce+);

my+$i+=
+++reduce+{+$array[$a]+<=+$array[$b]+?+$a+:+$b+}
++++++grep+{+$array[$_]+>=+0+}
+++++++++0..$#array;|code-block|syntax|javascript|89055|89056|如果你想要最优的性能，下面的内容会让你更接近：|89057|use+Config+++++qw(+%25Config+);
use+List::Util+qw(+minstr+);

my+$i+=
+++unpack+"x$Config{ivsize}+J",
++++++minstr
+++++++++map+{+pack+'J>+J',+$array[$_],+$_+}
++++++++++++grep+{+$array[$_]+>=+0+}
+++++++++++++++0..$#array;|89058|entityMap^0|F|4|P|6|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|W|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|X|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|Y|8|@]|D|@]|E|$]]|$1|N|3|O|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|P|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|Q|$]]

You want to <code>reduce</code> (O(N)), not <code>sort</code> (O(N log N))!

<pre><code>use List::Util qw( reduce );

my $i =
 reduce { $array[$a] &lt;= $array[$b] ? $a : $b }
 grep { $array[$_] &gt;= 0 }
 0..$#array;
</code></pre>

<hr>

If you want optimal performance, the following will get you closer:

<pre><code>use Config qw( %Config );
use List::Util qw( minstr );

my $i =
 unpack "x$Config{ivsize} J",
 minstr
 map { pack 'J&gt; J', $array[$_], $_ }
 grep { $array[$_] &gt;= 0 }
 0..$#array;
</code></pre>

blocks|key|2820464|text|最快的方法是扫描列表。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2820465|#!/usr/bin/env+perl

#+always+use+these+two
use+strict;
use+warnings;

use+feature+qw(+:all+);

#+--------------------------------------
#+++++++Name:+smallest_whole_number
#++++++Usage:+(+$smallest,+$index+)+=+smallest_whole_number(+@array+);
#++++Purpose:+Find+the+smallest+whole+number+in+an+array.
#+Parameters:+@array+--+array+of+integers
#++++Returns:+(+$smallest,+$index+)+unless+exception.
#+++++++++++++(+-1,+-1+)+if+exception.
#
sub+smallest_whole_number+{
++++my+@array+=+@_;

++++#+check+if+array+empty
++++return+(+-1,+-1+)+unless+@array;

++++#+scan+for+first+whole+number
++++my+$index+=+0;
++++while(+$array[$index]+<+0+){

++++++++#+exception+if+no+whole+numbers+in+array
++++++++return+(+-1,+-1+)+if+$index+>=+$#array;

++++++++$index+%2B%2B;
++++}

++++#+save+first+whole+number+found
++++my+$smallest+=+$array[$index];

++++#+scan+the+rest+of+the+array
++++for(+my+$i+=+$index+%2B+1;+$i+<=+$#array;+$i+%2B%2B+){
++++++++my+$nbr+=+$array[$i];

++++++++#+skip+negative+numbers
++++++++next+if+$nbr+<+0;

++++++++#+check+if+current+number+smaller
++++++++if(+$smallest+>+$nbr+){
++++++++++++$smallest+=+$nbr;
++++++++++++$index++++=+$i;
++++++++}
++++}

++++return+(+$smallest,+$index+);
}

#+--------------------------------------
#+main

my+@array+=+('3',+'4',+'71',+'1',+'-598',+'-100203');

my+(+$smallest,+$index+)+=+smallest_whole_number(+@array+);
say+"smallest+is+$smallest+at+index+$index";|code-block|syntax|javascript|2820466|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The quickest way is to scan the list.

<pre><code>#!/usr/bin/env perl

# always use these two
use strict;
use warnings;

use feature qw( :all );

# --------------------------------------
# Name: smallest_whole_number
# Usage: ( $smallest, $index ) = smallest_whole_number( @array );
# Purpose: Find the smallest whole number in an array.
# Parameters: @array -- array of integers
# Returns: ( $smallest, $index ) unless exception.
# ( -1, -1 ) if exception.
#
sub smallest_whole_number {
 my @array = @_;

 # check if array empty
 return ( -1, -1 ) unless @array;

 # scan for first whole number
 my $index = 0;
 while( $array[$index] &lt; 0 ){

 # exception if no whole numbers in array
 return ( -1, -1 ) if $index &gt;= $#array;

 $index ++;
 }

 # save first whole number found
 my $smallest = $array[$index];

 # scan the rest of the array
 for( my $i = $index + 1; $i &lt;= $#array; $i ++ ){
 my $nbr = $array[$i];

 # skip negative numbers
 next if $nbr &lt; 0;

 # check if current number smaller
 if( $smallest &gt; $nbr ){
 $smallest = $nbr;
 $index = $i;
 }
 }

 return ( $smallest, $index );
}

# --------------------------------------
# main

my @array = ('3', '4', '71', '1', '-598', '-100203');

my ( $smallest, $index ) = smallest_whole_number( @array );
say "smallest is $smallest at index $index";
</code></pre>

I have an array which looks like this

<pre><code>@array = ('3', '4', '71', '1', '-598', '-100203');
</code></pre>

I want to find the index of the smallest non-negative number among the integers in the array.

For this case:

<ul>
<li>smallest non-negative number = 1</li>
<li>index of smallest non-negative number = 3</li>
</ul>

Get the index of smallest non-negative number in an array?

我有一个数组，看起来像这样@array = ('3', '4', '71', '1', '-598', '-100203');我想找出数组中整数中最小的非负数的索引。对于这种情况：最小非负数=1最小非负数的索引= 3

问获取数组中最小非负数的索引？
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