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Perl Data Language (abbreviated PDL) is a set of free software array programming extensions to the Perl programming language. PDL extends the data structures built into Perl, to include large multidimensional arrays , and adds functionality to manipulate those arrays as vector objects.
The number of elements in an array can be determined either by evaluating the array in scalar context or with the help of the $# sigil. The latter gives the index of the last element in the array, not the number of elements. The expressions scalar(@array) and ($#array + 1) are equivalent.
In C, strings are normally represented as a character array rather than an actual string data type. The fact a string is really an array of characters means that referring to a string would mean referring to the first element in an array. Hence in C, the following is a legitimate example of brace notation:
In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine. For example, if x is an array, then y = sin (x) will result in an array y whose elements are sine of the corresponding elements of the array x. Vectorized index operations are also supported.
Perl Programming Documentation, also called perldoc, is the name of the user manual for the Perl 5 programming language. It is available in several different formats, including online in HTML and PDF. The documentation is bundled with Perl in its own format, known as Plain Old Documentation (pod).
Perl 5 has built-in, language-level support for associative arrays. Modern Perl refers to associative arrays as hashes; the term associative array is found in older documentation but is considered somewhat archaic. Perl 5 hashes are flat: keys are strings and values are scalars.
Common examples of array slicing are extracting a substring from a string of characters, the "ell" in "hello", extracting a row or column from a two-dimensional array, or extracting a vector from a matrix. Depending on the programming language, an array slice can be made out of non-consecutive elements.
In these languages, including the line __DATA__ (Perl) or __END__ (Ruby, old Perl) marks the end of the code segment and the start of the data segment. Only the contents prior to this line are executed, and the contents of the source file after this line are available as a file object: PACKAGE::DATA in Perl (e.g., main::DATA) and DATA in Ruby ...