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  instead. If you want to make a new table with no shared subtables and without metatables transferred, use  with the   option.

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   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   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,  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 ,   will return. All characters in  and   are interpreted literally.

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

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. Any keys that are not positive integers are removed. For example, for the table,  will return.

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

Usually  is used in a generic   loop.

Note that  uses the   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,  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  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  function, which follows the same rules as the   function supplied to. If  is , no sorting is done. Set  to   to skip the internal type checking.

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

isArray
Returns  if   is a table and all keys are consecutive integers starting at 1.

isArrayLike
Returns  if   is iterable and all keys are consecutive integers starting at 1.

invert
Transposes the keys and values in an array. For example, invert{ "a", "b", "c" } yields.

listToSet
Creates a set from the array part of the table. Indexing the set by any of the values of the array returns. For example, listToSet{ "a", "b", "c" } yields.

deepCopy
Creates a copy of the table. As with, all values that are not functions are duplicated and the identity of tables is preserved. If  is , then the metatable (if any) is not copied. Can copy tables loaded with.

Similar to, but   cannot copy tables loaded with   and does not allow metatables not to be copied.

sparseConcat
Concatenates all values in the table that are indexed by a positive integer, in order. For example, sparseConcat{ "a", nil, "c", "d" } yields "acd" and sparseConcat{ nil, "b", "c", "d" } yields "bcd".

length
Finds the length of an array or of a quasi-array with keys with an optional  such as "data1", "data2", etc. It uses an exponential search algorithm to find the length, so as to use as few table lookups as possible.

This algorithm is useful for arrays that use metatables (e.g. frame.args) and for quasi-arrays. For normal arrays, just use the # operator, as it is implemented in C and will be quicker.

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

merge
Given the arrays, returns an array containing the elements of each input array in sequence.

extend
Extends the first array in place by appending all elements from the second array.