Rename arrays concept to arrays-and-lists

concepts/arrays-and-lists/introduction.md

@@ -0,0 +1,65 @@
+# Introduction
+
+Arrays and lists contain an ordered collection of scalars.
+Outside of using references (which will be covered in a separate concept), this means that arrays and lists are always flat, i.e., they cannot contain other arrays or lists.
+
+In most cases, lists are surrounded by parentheses `()` with their elements separated by commas `,`.
+
+An array variable is usually populated by assigning a list to it, e.g., `my @names = ('Alice', 'Bob', 'Charlie');`.
+
+Elements of an array or list can be accessed by specifying indexes via a subscript, e.g., `('Alice', 'Bob', 'Charlie')[1] # 'Bob'`.
+
+Indexes in Perl start at `0`.
+Negative indexes will count from the end of the array or list, e.g., `('Alice', 'Bob', 'Charlie')[-1] # 'Charlie'`.
+
+## Functions
+
+There are many functions implemented for operating on arrays and lists, some of the most useful being [grep][grep] for a new list of filtered elements which match a condition, [map][map] for translating elements to a new list of values, and [sort][sort] for a new list of reordered elements.
+
+Functions for manipulating arrays include [push][push] to add elements to the end, [pop][pop] to remove the last element, [shift][shift] to remove the first element, [unshift][unshift] to add elements to the start, and [splice][splice] for more complex modifications.
+
+## Sigil Variance
+
+When accessing the elements of an array, the given sigil determines the result.
+The subscript `[]` at the end of the variable name is what tells Perl that you are accessing an array with that name.
+
+```perl
+my @names = ('Alice', 'Bob', 'Charlie');
+
+$names[0]; # 'Alice'      <- A scalar
+@names[0]; # ('Alice')    <- A slice (with only one index, this probably isn't what you want. There will be a warning.)
+%names[0]; # (0, 'Alice') <- A key/index + value slice
+
+$names[1, 2]; # 'Charlie'                <- A scalar (via unsupported syntax for an ancient feature. Probably not what you want. There will be a warning.)
+@names[1, 2]; # ('Bob', 'Charlie')       <- A slice
+%names[1, 2]; # (1, 'Bob', 2, 'Charlie') <- A key/index + value slice
+```
+
+While it is allowed, it is recommended to not have different variable types share the same name for the sake of readability.
+
+## Arrays vs Lists
+
+Arrays and lists share many similarities, and in a lot of places can be used interchangably, but they are not the same thing.
+A list is a fixed and immutable collection of scalars.
+An array is a variable collection of scalars where the contents and the size of the array itself can be changed.
+
+They have different behaviors in some contexts, for example, an array used in scalar context will give you the size of the array, while a list used in scalar context will give you the last element in the list, and potentially some warnings about the rest of its contents being used in void context.
+
+```perl
+my @names = ('Alice', 'Bob', 'Charlie');
+
+scalar @names; # 3
+scalar ('Alice', 'Bob', 'Charlie'); # 'Charlie' (and some warnings).
+```
+
+Read more in the folowing FAQ: [What is the difference between a list and an array?](perlfaq4listarray)
+
+[perlfaq4listarray]: https://perldoc.pl/perlfaq4#What-is-the-difference-between-a-list-and-an-array?
+[grep]: https://perldoc.pl/functions/grep
+[map]: https://perldoc.pl/functions/map
+[sort]: https://perldoc.pl/functions/sort
+[push]: https://perldoc.pl/functions/push
+[pop]: https://perldoc.pl/functions/pop
+[shift]: https://perldoc.pl/functions/shift
+[unshift]: https://perldoc.pl/functions/unshift
+[splice]: https://perldoc.pl/functions/splice

concepts/arrays-and-lists/links.json

@@ -0,0 +1,26 @@
+[
+  {
+    "description": "What is the difference between a list and an array?",
+    "url": "https://perldoc.pl/perlfaq4#What-is-the-difference-between-a-list-and-an-array?"
+  },
+  {
+    "description": "What is the difference between $array[1] and @array[1]?",
+    "url": "https://perldoc.pl/perlfaq4#What-is-the-difference-between-$array%5B1%5D-and-@array%5B1%5D?"
+  },
+  {
+    "description": "List Value Constructors",
+    "url": "https://perldoc.pl/perldata#List-value-constructors"
+  },
+  {
+    "description": "Subscripts",
+    "url": "https://perldoc.pl/perldata#Subscripts"
+  },
+  {
+    "description": "Slices",
+    "url": "https://perldoc.pl/perldata#Slices"
+  },
+  {
+    "description": "Index/Value Array Slices",
+    "url": "https://perldoc.perl.org/perldata#Index/Value-Array-Slices"
+  }
+]

config.json

@@ -53,7 +53,7 @@
         "name": "Language List",
         "uuid": "073a255f-011e-4264-89ea-69748d5fe71e",
         "concepts": [
-          "arrays"
+          "arrays-and-lists"
         ],
         "prerequisites": [
           "basics"
@@ -704,8 +704,8 @@
     },
     {
       "uuid": "9bf709d9-0667-4b1c-bd02-9b1c5ee292f9",
-      "slug": "arrays",
-      "name": "Arrays"
+      "slug": "arrays-and-lists",
+      "name": "Arrays and Lists"
     },
     {
       "uuid": "2d3c030e-0300-4b3e-8e1b-d115b86cdfa1",