My = sort this version of perl, the sort function is implemented via the mergesort algorithm. My = sort same thing, but with explicit sort routine perl-String-KeyboardDistance-1.01-1.2.el6.rf.noarch.html, String Comparison Algorithm, DAG packages for Red Hat. If stability matters, it can be controlled explicitly by using the sort pragma. Package, Summary, Distribution, Download. Historically Perl has varied in whether sorting is stable by default. This is usually something to be avoided when writing clear code. That is, modifying an element of a list returned by sort (for example, in a foreach, map or grep) actually modifies the element in the original list. Sort returns aliases into the original list, much as a for loop's index variable aliases the list elements. and begins matching the regex inside the lookahead. You might be thinking: If strings and integers are equivalent in Perl, why do we need two kinds of comparison. They do not consume characters in the string, but only assert whether a match is possible or not. When use locale (but not use locale ':not_characters') is in effect, sort LIST sorts LIST according to the current collation locale. String Comparison Versus Integer Comparison. Most who have been in contact with the command line in some form should be familiar with being used as a wildcard, and it has a similar use in Perl, matching any amount of the previous. Double quotes force an evaluation of what is inside the string. You also cannot exit out of the sort block or subroutine using any of the loop control operators described in perlsyn or with goto. The difference between single and double quotes on strings is significant. The values to be compared are always passed by reference and should not be modified. If the subroutine is an XSUB, the elements to be compared are pushed on to the stack, the way arguments are usually passed to XSUBs. This is slower than unprototyped subroutines, where the elements to be compared are passed into the subroutine as the package global variables $a and $b (see example below). If the subroutine's prototype is ($$), the elements to be compared are passed by reference in as for a normal subroutine. In place of a SUBNAME, you can provide a BLOCK as an anonymous, in-line sort subroutine. (The and cmp operators are extremely useful in such routines.) SUBNAME may be a scalar variable name (unsubscripted), in which case the value provides the name of (or a reference to) the actual subroutine to use. If SUBNAME is specified, it gives the name of a subroutine that returns an integer less than, equal to, or greater than 0, depending on how the elements of the list are to be ordered. ![]() If SUBNAME or BLOCK is omitted, sorts in standard string comparison order. ![]() In scalar context, the behaviour of sort is undefined. It also means that Perl has two versions of some operators, one for numeric and one for string comparison. In list context, this sorts the LIST and returns the sorted list value. For example x + y is always a numeric addition, and if x or y do not contain numbers, an attempt is made to convert them to numbers first. Sort may also refer to the module: sort # sort SUBNAME LIST # sort BLOCK LIST # sort LIST In Perl, the operator determines what operation is performed, independent of the type of the operands.
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