Module:TableTools/doc

This module includes a number of functions for dealing with Lua tables. It is a meta-module, meant to be called from other Lua modules, and should not be called directly from #invoke.

Loading the module
To use any of the functions, first you must load the module.

isPositiveInteger
Returns  if   is a positive integer, and   if not. Although it doesn't operate on tables, it is included here as it is useful for determining whether a given table key is in the array part or the hash part of a table.

isNan
Returns  if   is a NaN value, and   if not. Although it doesn't operate on tables, it is included here as it is useful for determining whether a value can be a valid table key. (Lua will generate an error if a NaN value is used as a table key.)

shallowClone
Returns a clone of a table. The value returned is a new table, but all subtables and functions are shared. Metamethods are respected, but the returned table will have no metatable of its own. If you want to make a new table with no shared subtables and with metatables transferred, you can use mw.clone instead.

removeDuplicates
Removes duplicate values from an array. This function is only designed to work with standard arrays: keys that are not positive integers are ignored, as are all values after the first  value. (For arrays containing  values, you can use compressSparseArray first.) The function tries to preserve the order of the array: the earliest non-unique value is kept, and all subsequent duplicate values are removed. For example, for the table removeDuplicates will return

numKeys
Takes a table  and returns an array containing the numbers of any positive integer keys that have non-nil values, sorted in numerical order. For example, for the table, numKeys will return.

affixNums
Takes a table  and returns an array containing the numbers of keys with the optional prefix   and the optional suffix. For example, for the table and the prefix , affixNums will return. All characters in  and   are interpreted literally.

numData
Given a table with keys like "foo1", "bar1", "foo2", and "baz2", returns a table of subtables in the format. Keys that don't end with an integer are stored in a subtable named "other". The compress option compresses the table so that it can be iterated over with ipairs.

compressSparseArray
Takes an array  with one or more nil values, and removes the nil values while preserving the order, so that the array can be safely traversed with ipairs. Any keys that are not positive integers are removed. For example, for the table, compressSparseArray will return.

sparseIpairs
This is an iterator function for traversing a sparse array. It is similar to ipairs, but will continue to iterate until the highest numerical key, whereas ipairs may stop after the first  value. Any keys that are not positive integers are ignored.

Usually sparseIpairs is used in a generic  loop.

Note that sparseIpairs uses the pairs function in its implementation. Although some table keys appear to be ignored, all table keys are accessed when it is run.

size
Finds the size of a key/value pair table. For example, for the table, size will return. The function will also work on arrays, but for arrays it is more efficient to use the # operator. Note that to find the table size, this function uses the pairs function to iterate through all of the table keys.

keysToList
Returns a list of the keys in a table, sorted using either a default comparison function or a custom keySort function.

sortedPairs
Iterates through a table, with the keys sorted using the keysToList function. If there are only numerical keys, sparseIpairs is probably more efficient.

isArray
Returns true if all keys in the table are consecutive integers starting at 1.

invert
Transposes the keys and values in a table.

sparseConcat
Concatenates all values in the table that are indexed by a number, in order.

length
returns the length of a table, or the first integer key n counting from 1 such that t[n + 1] is nil. It is similar to the operator #, but may return a different value when there are gaps in the array portion of the table. Intended to be used on data loaded with mw.loadData. For other tables, use #.

inArray
Returns  if valueToFind is a member of the array arr, and   otherwise.