{
    "mode": "perldoc",
    "parameter": "List::Util",
    "section": "",
    "url": "https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil/json",
    "generated": "2026-06-12T00:28:18Z",
    "synopsis": "use List::Util qw(\nreduce any all none notall first reductions\nmax maxstr min minstr product sum sum0\npairs unpairs pairkeys pairvalues pairfirst pairgrep pairmap\nshuffle uniq uniqint uniqnum uniqstr zip mesh\n);",
    "sections": {
        "NAME": {
            "content": "List::Util - A selection of general-utility list subroutines\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "use List::Util qw(\nreduce any all none notall first reductions\n\nmax maxstr min minstr product sum sum0\n\npairs unpairs pairkeys pairvalues pairfirst pairgrep pairmap\n\nshuffle uniq uniqint uniqnum uniqstr zip mesh\n);\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "\"List::Util\" contains a selection of subroutines that people have expressed would be nice to\nhave in the perl core, but the usage would not really be high enough to warrant the use of a\nkeyword, and the size so small such that being individual extensions would be wasteful.\n\nBy default \"List::Util\" does not export any subroutines.\n",
            "subsections": []
        },
        "LIST-REDUCTION FUNCTIONS": {
            "content": "The following set of functions all apply a given block of code to a list of values.\n\nreduce\n$result = reduce { BLOCK } @list\n\nReduces @list by calling \"BLOCK\" in a scalar context multiple times, setting $a and $b each\ntime. The first call will be with $a and $b set to the first two elements of the list,\nsubsequent calls will be done by setting $a to the result of the previous call and $b to the\nnext element in the list.\n\nReturns the result of the last call to the \"BLOCK\". If @list is empty then \"undef\" is returned.\nIf @list only contains one element then that element is returned and \"BLOCK\" is not executed.\n\nThe following examples all demonstrate how \"reduce\" could be used to implement the other\nlist-reduction functions in this module. (They are not in fact implemented like this, but\ninstead in a more efficient manner in individual C functions).\n\n$foo = reduce { defined($a)            ? $a :\n$code->(local $ = $b) ? $b :\nundef } undef, @list # first\n\n$foo = reduce { $a > $b ? $a : $b } 1..10       # max\n$foo = reduce { $a gt $b ? $a : $b } 'A'..'Z'   # maxstr\n$foo = reduce { $a < $b ? $a : $b } 1..10       # min\n$foo = reduce { $a lt $b ? $a : $b } 'aa'..'zz' # minstr\n$foo = reduce { $a + $b } 1 .. 10               # sum\n$foo = reduce { $a . $b } @bar                  # concat\n\n$foo = reduce { $a || $code->(local $ = $b) } 0, @bar   # any\n$foo = reduce { $a && $code->(local $ = $b) } 1, @bar   # all\n$foo = reduce { $a && !$code->(local $ = $b) } 1, @bar  # none\n$foo = reduce { $a || !$code->(local $ = $b) } 0, @bar  # notall\n# Note that these implementations do not fully short-circuit\n\nIf your algorithm requires that \"reduce\" produce an identity value, then make sure that you\nalways pass that identity value as the first argument to prevent \"undef\" being returned\n\n$foo = reduce { $a + $b } 0, @values;             # sum with 0 identity value\n\nThe above example code blocks also suggest how to use \"reduce\" to build a more efficient\ncombined version of one of these basic functions and a \"map\" block. For example, to find the\ntotal length of all the strings in a list, we could use\n\n$total = sum map { length } @strings;\n\nHowever, this produces a list of temporary integer values as long as the original list of\nstrings, only to reduce it down to a single value again. We can compute the same result more\nefficiently by using \"reduce\" with a code block that accumulates lengths by writing this instead\nas:\n\n$total = reduce { $a + length $b } 0, @strings\n\nThe other scalar-returning list reduction functions are all specialisations of this generic\nidea.\n\nreductions\n@results = reductions { BLOCK } @list\n\n*Since version 1.54.*\n\nSimilar to \"reduce\" except that it also returns the intermediate values along with the final\nresult. As before, $a is set to the first element of the given list, and the \"BLOCK\" is then\ncalled once for remaining item in the list set into $b, with the result being captured for\nreturn as well as becoming the new value for $a.\n\nThe returned list will begin with the initial value for $a, followed by each return value from\nthe block in order. The final value of the result will be identical to what the \"reduce\"\nfunction would have returned given the same block and list.\n\nreduce     { \"$a-$b\" }  \"a\"..\"d\"    # \"a-b-c-d\"\nreductions { \"$a-$b\" }  \"a\"..\"d\"    # \"a\", \"a-b\", \"a-b-c\", \"a-b-c-d\"\n\nany\nmy $bool = any { BLOCK } @list;\n\n*Since version 1.33.*\n\nSimilar to \"grep\" in that it evaluates \"BLOCK\" setting $ to each element of @list in turn.\n\"any\" returns true if any element makes the \"BLOCK\" return a true value. If \"BLOCK\" never\nreturns true or @list was empty then it returns false.\n\nMany cases of using \"grep\" in a conditional can be written using \"any\" instead, as it can\nshort-circuit after the first true result.\n\nif( any { length > 10 } @strings ) {\n# at least one string has more than 10 characters\n}\n\nNote: Due to XS issues the block passed may be able to access the outer @ directly. This is not\nintentional and will break under debugger.\n\nall\nmy $bool = all { BLOCK } @list;\n\n*Since version 1.33.*\n\nSimilar to \"any\", except that it requires all elements of the @list to make the \"BLOCK\" return\ntrue. If any element returns false, then it returns false. If the \"BLOCK\" never returns false or\nthe @list was empty then it returns true.\n\nNote: Due to XS issues the block passed may be able to access the outer @ directly. This is not\nintentional and will break under debugger.\n\nnone\nnotall\nmy $bool = none { BLOCK } @list;\n\nmy $bool = notall { BLOCK } @list;\n\n*Since version 1.33.*\n\nSimilar to \"any\" and \"all\", but with the return sense inverted. \"none\" returns true only if no\nvalue in the @list causes the \"BLOCK\" to return true, and \"notall\" returns true only if not all\nof the values do.\n\nNote: Due to XS issues the block passed may be able to access the outer @ directly. This is not\nintentional and will break under debugger.\n\nfirst\nmy $val = first { BLOCK } @list;\n\nSimilar to \"grep\" in that it evaluates \"BLOCK\" setting $ to each element of @list in turn.\n\"first\" returns the first element where the result from \"BLOCK\" is a true value. If \"BLOCK\"\nnever returns true or @list was empty then \"undef\" is returned.\n\n$foo = first { defined($) } @list    # first defined value in @list\n$foo = first { $ > $value } @list    # first value in @list which\n# is greater than $value\n\nmax\nmy $num = max @list;\n\nReturns the entry in the list with the highest numerical value. If the list is empty then\n\"undef\" is returned.\n\n$foo = max 1..10                # 10\n$foo = max 3,9,12               # 12\n$foo = max @bar, @baz           # whatever\n\nmaxstr\nmy $str = maxstr @list;\n\nSimilar to \"max\", but treats all the entries in the list as strings and returns the highest\nstring as defined by the \"gt\" operator. If the list is empty then \"undef\" is returned.\n\n$foo = maxstr 'A'..'Z'          # 'Z'\n$foo = maxstr \"hello\",\"world\"   # \"world\"\n$foo = maxstr @bar, @baz        # whatever\n\nmin\nmy $num = min @list;\n\nSimilar to \"max\" but returns the entry in the list with the lowest numerical value. If the list\nis empty then \"undef\" is returned.\n\n$foo = min 1..10                # 1\n$foo = min 3,9,12               # 3\n$foo = min @bar, @baz           # whatever\n\nminstr\nmy $str = minstr @list;\n\nSimilar to \"min\", but treats all the entries in the list as strings and returns the lowest\nstring as defined by the \"lt\" operator. If the list is empty then \"undef\" is returned.\n\n$foo = minstr 'A'..'Z'          # 'A'\n$foo = minstr \"hello\",\"world\"   # \"hello\"\n$foo = minstr @bar, @baz        # whatever\n\nproduct\nmy $num = product @list;\n\n*Since version 1.35.*\n\nReturns the numerical product of all the elements in @list. If @list is empty then 1 is\nreturned.\n\n$foo = product 1..10            # 3628800\n$foo = product 3,9,12           # 324\n\nsum\nmy $numorundef = sum @list;\n\nReturns the numerical sum of all the elements in @list. For backwards compatibility, if @list is\nempty then \"undef\" is returned.\n\n$foo = sum 1..10                # 55\n$foo = sum 3,9,12               # 24\n$foo = sum @bar, @baz           # whatever\n\nsum0\nmy $num = sum0 @list;\n\n*Since version 1.26.*\n\nSimilar to \"sum\", except this returns 0 when given an empty list, rather than \"undef\".\n",
            "subsections": []
        },
        "KEY/VALUE PAIR LIST FUNCTIONS": {
            "content": "The following set of functions, all inspired by List::Pairwise, consume an even-sized list of\npairs. The pairs may be key/value associations from a hash, or just a list of values. The\nfunctions will all preserve the original ordering of the pairs, and will not be confused by\nmultiple pairs having the same \"key\" value - nor even do they require that the first of each\npair be a plain string.\n\nNOTE: At the time of writing, the following \"pair*\" functions that take a block do not modify\nthe value of $ within the block, and instead operate using the $a and $b globals instead. This\nhas turned out to be a poor design, as it precludes the ability to provide a \"pairsort\"\nfunction. Better would be to pass pair-like objects as 2-element array references in $, in a\nstyle similar to the return value of the \"pairs\" function. At some future version this behaviour\nmay be added.\n\nUntil then, users are alerted NOT to rely on the value of $ remaining unmodified between the\noutside and the inside of the control block. In particular, the following example is UNSAFE:\n\nmy @kvlist = ...\n\nforeach (qw( some keys here )) {\nmy @items = pairgrep { $a eq $ } @kvlist;\n...\n}\n\nInstead, write this using a lexical variable:\n\nforeach my $key (qw( some keys here )) {\nmy @items = pairgrep { $a eq $key } @kvlist;\n...\n}\n\npairs\nmy @pairs = pairs @kvlist;\n\n*Since version 1.29.*\n\nA convenient shortcut to operating on even-sized lists of pairs, this function returns a list of\n\"ARRAY\" references, each containing two items from the given list. It is a more efficient\nversion of\n\n@pairs = pairmap { [ $a, $b ] } @kvlist\n\nIt is most convenient to use in a \"foreach\" loop, for example:\n\nforeach my $pair ( pairs @kvlist ) {\nmy ( $key, $value ) = @$pair;\n...\n}\n\nSince version 1.39 these \"ARRAY\" references are blessed objects, recognising the two methods\n\"key\" and \"value\". The following code is equivalent:\n\nforeach my $pair ( pairs @kvlist ) {\nmy $key   = $pair->key;\nmy $value = $pair->value;\n...\n}\n\nSince version 1.51 they also have a \"TOJSON\" method to ease serialisation.\n\nunpairs\nmy @kvlist = unpairs @pairs\n\n*Since version 1.42.*\n\nThe inverse function to \"pairs\"; this function takes a list of \"ARRAY\" references containing two\nelements each, and returns a flattened list of the two values from each of the pairs, in order.\nThis is notionally equivalent to\n\nmy @kvlist = map { @{$}[0,1] } @pairs\n\nexcept that it is implemented more efficiently internally. Specifically, for any input item it\nwill extract exactly two values for the output list; using \"undef\" if the input array references\nare short.\n\nBetween \"pairs\" and \"unpairs\", a higher-order list function can be used to operate on the pairs\nas single scalars; such as the following near-equivalents of the other \"pair*\" higher-order\nfunctions:\n\n@kvlist = unpairs grep { FUNC } pairs @kvlist\n# Like pairgrep, but takes $ instead of $a and $b\n\n@kvlist = unpairs map { FUNC } pairs @kvlist\n# Like pairmap, but takes $ instead of $a and $b\n\nNote however that these versions will not behave as nicely in scalar context.\n\nFinally, this technique can be used to implement a sort on a keyvalue pair list; e.g.:\n\n@kvlist = unpairs sort { $a->key cmp $b->key } pairs @kvlist\n\npairkeys\nmy @keys = pairkeys @kvlist;\n\n*Since version 1.29.*\n\nA convenient shortcut to operating on even-sized lists of pairs, this function returns a list of\nthe the first values of each of the pairs in the given list. It is a more efficient version of\n\n@keys = pairmap { $a } @kvlist\n\npairvalues\nmy @values = pairvalues @kvlist;\n\n*Since version 1.29.*\n\nA convenient shortcut to operating on even-sized lists of pairs, this function returns a list of\nthe the second values of each of the pairs in the given list. It is a more efficient version of\n\n@values = pairmap { $b } @kvlist\n\npairgrep\nmy @kvlist = pairgrep { BLOCK } @kvlist;\n\nmy $count = pairgrep { BLOCK } @kvlist;\n\n*Since version 1.29.*\n\nSimilar to perl's \"grep\" keyword, but interprets the given list as an even-sized list of pairs.\nIt invokes the \"BLOCK\" multiple times, in scalar context, with $a and $b set to successive pairs\nof values from the @kvlist.\n\nReturns an even-sized list of those pairs for which the \"BLOCK\" returned true in list context,\nor the count of the number of pairs in scalar context. (Note, therefore, in scalar context that\nit returns a number half the size of the count of items it would have returned in list context).\n\n@subset = pairgrep { $a =~ m/^[[:upper:]]+$/ } @kvlist\n\nAs with \"grep\" aliasing $ to list elements, \"pairgrep\" aliases $a and $b to elements of the\ngiven list. Any modifications of it by the code block will be visible to the caller.\n\npairfirst\nmy ( $key, $val ) = pairfirst { BLOCK } @kvlist;\n\nmy $found = pairfirst { BLOCK } @kvlist;\n\n*Since version 1.30.*\n\nSimilar to the \"first\" function, but interprets the given list as an even-sized list of pairs.\nIt invokes the \"BLOCK\" multiple times, in scalar context, with $a and $b set to successive pairs\nof values from the @kvlist.\n\nReturns the first pair of values from the list for which the \"BLOCK\" returned true in list\ncontext, or an empty list of no such pair was found. In scalar context it returns a simple\nboolean value, rather than either the key or the value found.\n\n( $key, $value ) = pairfirst { $a =~ m/^[[:upper:]]+$/ } @kvlist\n\nAs with \"grep\" aliasing $ to list elements, \"pairfirst\" aliases $a and $b to elements of the\ngiven list. Any modifications of it by the code block will be visible to the caller.\n\npairmap\nmy @list = pairmap { BLOCK } @kvlist;\n\nmy $count = pairmap { BLOCK } @kvlist;\n\n*Since version 1.29.*\n\nSimilar to perl's \"map\" keyword, but interprets the given list as an even-sized list of pairs.\nIt invokes the \"BLOCK\" multiple times, in list context, with $a and $b set to successive pairs\nof values from the @kvlist.\n\nReturns the concatenation of all the values returned by the \"BLOCK\" in list context, or the\ncount of the number of items that would have been returned in scalar context.\n\n@result = pairmap { \"The key $a has value $b\" } @kvlist\n\nAs with \"map\" aliasing $ to list elements, \"pairmap\" aliases $a and $b to elements of the given\nlist. Any modifications of it by the code block will be visible to the caller.\n\nSee \"KNOWN BUGS\" for a known-bug with \"pairmap\", and a workaround.\n",
            "subsections": []
        },
        "OTHER FUNCTIONS": {
            "content": "shuffle\nmy @values = shuffle @values;\n\nReturns the values of the input in a random order\n\n@cards = shuffle 0..51      # 0..51 in a random order\n\nThis function is affected by the $RAND variable.\n\nsample\nmy @items = sample $count, @values\n\n*Since version 1.54.*\n\nRandomly select the given number of elements from the input list. Any given position in the\ninput list will be selected at most once.\n\nIf there are fewer than $count items in the list then the function will return once all of them\nhave been randomly selected; effectively the function behaves similarly to \"shuffle\".\n\nThis function is affected by the $RAND variable.\n\nuniq\nmy @subset = uniq @values\n\n*Since version 1.45.*\n\nFilters a list of values to remove subsequent duplicates, as judged by a DWIM-ish string\nequality or \"undef\" test. Preserves the order of unique elements, and retains the first value of\nany duplicate set.\n\nmy $count = uniq @values\n\nIn scalar context, returns the number of elements that would have been returned as a list.\n\nThe \"undef\" value is treated by this function as distinct from the empty string, and no warning\nwill be produced. It is left as-is in the returned list. Subsequent \"undef\" values are still\nconsidered identical to the first, and will be removed.\n\nuniqint\nmy @subset = uniqint @values\n\n*Since version 1.55.*\n\nFilters a list of values to remove subsequent duplicates, as judged by an integer numerical\nequality test. Preserves the order of unique elements, and retains the first value of any\nduplicate set. Values in the returned list will be coerced into integers.\n\nmy $count = uniqint @values\n\nIn scalar context, returns the number of elements that would have been returned as a list.\n\nNote that \"undef\" is treated much as other numerical operations treat it; it compares equal to\nzero but additionally produces a warning if such warnings are enabled (\"use warnings\n'uninitialized';\"). In addition, an \"undef\" in the returned list is coerced into a numerical\nzero, so that the entire list of values returned by \"uniqint\" are well-behaved as integers.\n\nuniqnum\nmy @subset = uniqnum @values\n\n*Since version 1.44.*\n\nFilters a list of values to remove subsequent duplicates, as judged by a numerical equality\ntest. Preserves the order of unique elements, and retains the first value of any duplicate set.\n\nmy $count = uniqnum @values\n\nIn scalar context, returns the number of elements that would have been returned as a list.\n\nNote that \"undef\" is treated much as other numerical operations treat it; it compares equal to\nzero but additionally produces a warning if such warnings are enabled (\"use warnings\n'uninitialized';\"). In addition, an \"undef\" in the returned list is coerced into a numerical\nzero, so that the entire list of values returned by \"uniqnum\" are well-behaved as numbers.\n\nNote also that multiple IEEE \"NaN\" values are treated as duplicates of each other, regardless of\nany differences in their payloads, and despite the fact that \"0+'NaN' == 0+'NaN'\" yields false.\n\nuniqstr\nmy @subset = uniqstr @values\n\n*Since version 1.45.*\n\nFilters a list of values to remove subsequent duplicates, as judged by a string equality test.\nPreserves the order of unique elements, and retains the first value of any duplicate set.\n\nmy $count = uniqstr @values\n\nIn scalar context, returns the number of elements that would have been returned as a list.\n\nNote that \"undef\" is treated much as other string operations treat it; it compares equal to the\nempty string but additionally produces a warning if such warnings are enabled (\"use warnings\n'uninitialized';\"). In addition, an \"undef\" in the returned list is coerced into an empty\nstring, so that the entire list of values returned by \"uniqstr\" are well-behaved as strings.\n\nhead\nmy @values = head $size, @list;\n\n*Since version 1.50.*\n\nReturns the first $size elements from @list. If $size is negative, returns all but the last\n$size elements from @list.\n\n@result = head 2, qw( foo bar baz );\n# foo, bar\n\n@result = head -2, qw( foo bar baz );\n# foo\n\ntail\nmy @values = tail $size, @list;\n\n*Since version 1.50.*\n\nReturns the last $size elements from @list. If $size is negative, returns all but the first\n$size elements from @list.\n\n@result = tail 2, qw( foo bar baz );\n# bar, baz\n\n@result = tail -2, qw( foo bar baz );\n# baz\n\nzip\nmy @result = zip [1..3], ['a'..'c'];\n# [1, 'a'], [2, 'b'], [3, 'c']\n\n*Since version 1.56.*\n\nReturns a list of array references, composed of elements from the given list of array\nreferences. Each array in the returned list is composed of elements at that corresponding\nposition from each of the given input arrays. If any input arrays run out of elements before\nothers, then \"undef\" will be inserted into the result to fill in the gaps.\n\nThe \"zip\" function is particularly handy for iterating over multiple arrays at the same time\nwith a \"foreach\" loop, taking one element from each:\n\nforeach ( zip \\@xs, \\@ys, \\@zs ) {\nmy ($x, $y, $z) = @$;\n...\n}\n\nNOTE to users of List::MoreUtils: This function does not behave the same as\n\"List::MoreUtils::zip\", but is actually a non-prototyped equivalent to\n\"List::MoreUtils::zipunflatten\". This function does not apply a prototype, so make sure to\ninvoke it with references to arrays.\n\nFor a function similar to the \"zip\" function from \"List::MoreUtils\", see mesh.\n\nmy @result = zipshortest ...\n\nA variation of the function that differs in how it behaves when given input arrays of differing\nlengths. \"zipshortest\" will stop as soon as any one of the input arrays run out of elements,\ndiscarding any remaining unused values from the others.\n\nmy @result = ziplongest ...\n\n\"ziplongest\" is an alias to the \"zip\" function, provided simply to be explicit about that\nbehaviour as compared to \"zipshortest\".\n\nmesh\nmy @result = mesh [1..3], ['a'..'c'];\n# (1, 'a', 2, 'b', 3, 'c')\n\n*Since version 1.56.*\n\nReturns a list of items collected from elements of the given list of array references. Each\nsection of items in the returned list is composed of elements at the corresponding position from\neach of the given input arrays. If any input arrays run out of elements before others, then\n\"undef\" will be inserted into the result to fill in the gaps.\n\nThis is similar to zip, except that all of the ranges in the result are returned in one long\nflattened list, instead of being bundled into separate arrays.\n\nBecause it returns a flat list of items, the \"mesh\" function is particularly useful for building\na hash out of two separate arrays of keys and values:\n\nmy %hash = mesh \\@keys, \\@values;\n\nmy $href = { mesh \\@keys, \\@values };\n\nNOTE to users of List::MoreUtils: This function is a non-prototyped equivalent to\n\"List::MoreUtils::mesh\" or \"List::MoreUtils::zip\" (themselves aliases of each other). This\nfunction does not apply a prototype, so make sure to invoke it with references to arrays.\n\nmy @result = meshshortest ...\n\nmy @result = meshlongest ...\n\nThese variations are similar to those of zip, in that they differ in behaviour when one of the\ninput lists runs out of elements before the others.\n",
            "subsections": []
        },
        "CONFIGURATION VARIABLES": {
            "content": "$RAND\nlocal $List::Util::RAND = sub { ... };\n\n*Since version 1.54.*\n\nThis package variable is used by code which needs to generate random numbers (such as the\n\"shuffle\" and \"sample\" functions). If set to a CODE reference it provides an alternative to\nperl's builtin \"rand()\" function. When a new random number is needed this function will be\ninvoked with no arguments and is expected to return a floating-point value, of which only the\nfractional part will be used.\n",
            "subsections": []
        },
        "KNOWN BUGS": {
            "content": "RT #95409\n<https://rt.cpan.org/Ticket/Display.html?id=95409>\n\nIf the block of code given to \"pairmap\" contains lexical variables that are captured by a\nreturned closure, and the closure is executed after the block has been re-used for the next\niteration, these lexicals will not see the correct values. For example:\n\nmy @subs = pairmap {\nmy $var = \"$a is $b\";\nsub { print \"$var\\n\" };\n} one => 1, two => 2, three => 3;\n\n$->() for @subs;\n\nWill incorrectly print\n\nthree is 3\nthree is 3\nthree is 3\n\nThis is due to the performance optimisation of using \"MULTICALL\" for the code block, which means\nthat fresh SVs do not get allocated for each call to the block. Instead, the same SV is\nre-assigned for each iteration, and all the closures will share the value seen on the final\niteration.\n\nTo work around this bug, surround the code with a second set of braces. This creates an inner\nblock that defeats the \"MULTICALL\" logic, and does get fresh SVs allocated each time:\n\nmy @subs = pairmap {\n{\nmy $var = \"$a is $b\";\nsub { print \"$var\\n\"; }\n}\n} one => 1, two => 2, three => 3;\n\nThis bug only affects closures that are generated by the block but used afterwards. Lexical\nvariables that are only used during the lifetime of the block's execution will take their\nindividual values for each invocation, as normal.\n\nuniqnum() on oversized bignums\nDue to the way that \"uniqnum()\" compares numbers, it cannot distinguish differences between\nbignums (especially bigints) that are too large to fit in the native platform types. For\nexample,\n\nmy $x = Math::BigInt->new( \"1\" x 100 );\nmy $y = $x + 1;\n\nsay for uniqnum( $x, $y );\n\nWill print just the value of $x, believing that $y is a numerically- equivalent value. This bug\ndoes not affect \"uniqstr()\", which will correctly observe that the two values stringify to\ndifferent strings.\n",
            "subsections": []
        },
        "SUGGESTED ADDITIONS": {
            "content": "The following are additions that have been requested, but I have been reluctant to add due to\nthem being very simple to implement in perl\n\n# How many elements are true\n\nsub true { scalar grep { $ } @ }\n\n# How many elements are false\n\nsub false { scalar grep { !$ } @ }\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "Scalar::Util, List::MoreUtils\n",
            "subsections": []
        },
        "COPYRIGHT": {
            "content": "Copyright (c) 1997-2007 Graham Barr <gbarr@pobox.com>. All rights reserved. This program is free\nsoftware; you can redistribute it and/or modify it under the same terms as Perl itself.\n\nRecent additions and current maintenance by Paul Evans, <leonerd@leonerd.org.uk>.\n",
            "subsections": []
        }
    },
    "summary": "List::Util - A selection of general-utility list subroutines",
    "flags": [],
    "examples": [],
    "see_also": []
}