Difference between revisions of "Module:TableTools/doc"
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| − | This module includes a number of functions for dealing with Lua tables. It is a | + | 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 {{code|#invoke}}. |
== Loading the module == | == Loading the module == | ||
| Line 15: | Line 15: | ||
</source> | </source> | ||
| − | Returns | + | Returns {{code|true}} if {{code|''value''}} is a positive integer, and {{code|false}} 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 == | == isNan == | ||
| Line 23: | Line 23: | ||
</source> | </source> | ||
| − | Returns | + | Returns {{code|true}} if {{code|''value''}} is a not a number value, and {{code|false}} 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 == | == shallowClone == | ||
| Line 31: | Line 31: | ||
</source> | </source> | ||
| − | 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 <code>[[mw:Extension:Scribunto/Lua reference manual#mw.clone|mw.clone]]</code> instead. If you want to make a new table with no shared subtables and without metatables transferred, use <code>[[#deepCopy|deepCopy]]</code> with the | + | 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 <code>[[mw:Extension:Scribunto/Lua reference manual#mw.clone|mw.clone]]</code> instead. If you want to make a new table with no shared subtables and without metatables transferred, use <code>[[#deepCopy|deepCopy]]</code> with the {{code|noMetatable}} option. |
== removeDuplicates == | == removeDuplicates == | ||
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</source> | </source> | ||
| − | 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 | + | 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 {{code|nil}} value. (For arrays containing {{code|nil}} values, you can use <code>[[#compressSparseArray|compressSparseArray]]</code> 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 {{code|code={5, 4, 4, 3, 4, 2, 2, 1}|lang=lua}} {{code|removeDuplicates}} will return {{code|code={5, 4, 3, 2, 1}|lang=lua}} |
== numKeys == | == numKeys == | ||
| Line 47: | Line 47: | ||
</source> | </source> | ||
| − | Takes a table | + | Takes a table {{code|''t''}} 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 {{code|code={'foo', nil, 'bar', 'baz', a = 'b'}|lang=lua}}, {{code|numKeys}} will return {{code|code={1, 3, 4}|lang=lua}}. |
== affixNums == | == affixNums == | ||
| Line 55: | Line 55: | ||
</source> | </source> | ||
| − | Takes a table | + | Takes a table {{code|''t''}} and returns an array containing the numbers of keys with the optional prefix {{code|''prefix''}} and the optional suffix {{code|''suffix''}}. For example, for the table {{code|code={a1 = 'foo', a3 = 'bar', a6 = 'baz'}|lang=lua}} and the prefix {{code|'a'}}, {{code|affixNums}} will return {{code|code={1, 3, 6}|lang=lua}}. All characters in {{code|''prefix''}} and {{code|''suffix''}} are interpreted literally. |
== numData == | == numData == | ||
| Line 63: | Line 63: | ||
</source> | </source> | ||
| − | Given a table with keys like | + | Given a table with keys like {{code|"foo1"}}, {{code|"bar1"}}, {{code|"foo2"}}, and {{code|"baz2"}}, returns a table of subtables in the format {{code|code={ [1] = {foo = 'text', bar = 'text'}, [2] = {foo = 'text', baz = 'text'} }|lang=lua}}. Keys that don’t end with an integer are stored in a subtable named {{code|"other"}}. The compress option compresses the table so that it can be iterated over with {{code|ipairs}}. |
== compressSparseArray == | == compressSparseArray == | ||
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</source> | </source> | ||
| − | Takes an array | + | Takes an array {{code|''t''}} with one or more nil values, and removes the nil values while preserving the order, so that the array can be safely traversed with {{code|ipairs}}. Any keys that are not positive integers are removed. For example, for the table {{code|code={1, nil, foo = 'bar', 3, 2}|lang=lua}}, {{code|compressSparseArray}} will return {{code|code={1, 3, 2}|lang=lua}}. |
== sparseIpairs == | == sparseIpairs == | ||
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</source> | </source> | ||
| − | This is an iterator function for traversing a sparse array | + | This is an iterator function for traversing a sparse array {{code|''t''}}. It is similar to <code>[[mw:Extension:Scribunto/Lua reference manual#ipairs|ipairs]]</code>, but will continue to iterate until the highest numerical key, whereas {{code|ipairs}} may stop after the first {{code|nil}} value. Any keys that are not positive integers are ignored. |
| − | Usually | + | Usually {{code|sparseIpairs}} is used in a generic {{code|for}} loop. |
<source lang="lua"> | <source lang="lua"> | ||
| Line 89: | Line 89: | ||
</source> | </source> | ||
| − | Note that | + | Note that {{code|sparseIpairs}} uses the <code>[[mw:Extension:Scribunto/Lua reference manual#pairs|pairs]]</code> function in its implementation. Although some table keys appear to be ignored, all table keys are accessed when it is run. |
== size == | == size == | ||
| Line 97: | Line 97: | ||
</source> | </source> | ||
| − | Finds the size of a key/value pair table. For example, for the table {{code|code={foo = 'foo', bar = 'bar'}|lang=lua}}, | + | Finds the size of a key/value pair table. For example, for the table {{code|code={foo = 'foo', bar = 'bar'}|lang=lua}}, {{code|size}} will return {{code|2}}. The function will also work on arrays, but for arrays it is more efficient to use the {{code|#}} operator. Note that to find the table size, this function uses the <code>[[mw:Extension:Scribunto/Lua reference manual#pairs|pairs]]</code> function to iterate through all of the table keys. |
== keysToList == | == keysToList == | ||
| Line 105: | Line 105: | ||
</source> | </source> | ||
| − | Returns a list of the keys in a table, sorted using either a default comparison function or a custom | + | Returns a list of the keys in a table, sorted using either a default comparison function or a custom {{code|keySort}} function, which follows the same rules as the {{code|comp}} function supplied to <code>[[mw:Extension:Scribunto/Lua reference manual#table.sort|table.sort]]</code>. |
== sortedPairs == | == sortedPairs == | ||
| Line 113: | Line 113: | ||
</source> | </source> | ||
| − | Iterates through a table, with the keys sorted using the | + | Iterates through a table, with the keys sorted using the {{code|keysToList}} function. If there are only numerical keys, {{code|sparseIpairs}} is probably more efficient. |
== isArray == | == isArray == | ||
| Line 121: | Line 121: | ||
</source> | </source> | ||
| − | Returns true if all keys in the table are consecutive integers starting at | + | Returns true if all keys in the table are consecutive integers starting at {{code|1}}. |
== listToSet == | == listToSet == | ||
| Line 129: | Line 129: | ||
</source> | </source> | ||
| − | Creates a set from the array part of the table | + | Creates a set from the array part of the table {{code|arr}}. Indexing the set by any of the values in {{code|arr}} returns {{code|true}}. |
<source lang="lua"> | <source lang="lua"> | ||
| Line 150: | Line 150: | ||
</source> | </source> | ||
| − | Creates a copy of the table | + | Creates a copy of the table {{code|orig}}. As with <code>mw.clone</code>, all values that are not functions are duplicated and the identity of tables is preserved. If {{code|noMetatable}} is {{code|true}}, then the metatable (if any) is not copied. Can copy tables loaded with <code>mw.loadData</code>. |
| − | Similar to | + | Similar to {{code|mw.clone}}, but {{code|mw.clone}} cannot copy tables loaded with {{code|mw.loadData}} and does not allow metatables {{em|not}} to be copied. |
== sparseConcat == | == sparseConcat == | ||
| Line 168: | Line 168: | ||
</source> | </source> | ||
| − | Returns the length of a table, or the first integer key | + | Returns the length of a table, or the first integer key {{code|n}} counting from {{code|0}} such that {{code|t[n + 1]}} is {{code|nil}}. It is similar to the operator {{code|#}}, 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 <code>[[mw:Extension:Scribunto/Lua reference manual#mw.loadData|mw.loadData]]</code> and on <code>[[mw:Extension:Scribunto/Lua reference manual#frame.args|frame.args]]</code>. Both use a metatable such that {{code|#mw.loadData("module:...")}} and {{code|#frame.args}} don’t work correctly. For other tables, use {{code|#}}. |
== inArray == | == inArray == | ||
| Line 176: | Line 176: | ||
</source> | </source> | ||
| − | Returns <syntaxhighlight lang="lua" inline>true</syntaxhighlight> if | + | Returns <syntaxhighlight lang="lua" inline>true</syntaxhighlight> if {{code|valueToFind}} is a member of the array {{code|arr}}, and <syntaxhighlight lang="lua" inline>false</syntaxhighlight> otherwise. |
| − | [[Category:Modules]] | + | [[Category:Modules]][[Category:Modules documentation]] |
Revision as of 17:08, 11 July 2020
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.
Contents
Loading the module
To use any of the functions, first you must load the module.
local TableTools = require('Module:TableTools')
isPositiveInteger
TableTools.isPositiveInteger(value)
Returns true if ''value'' is a positive integer, and false 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
TableTools.isNan(value)
Returns true if ''value'' is a not a number value, and false 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
TableTools.shallowClone(t)
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. If you want to make a new table with no shared subtables and without metatables transferred, use deepCopy with the noMetatable option.
removeDuplicates
TableTools.removeDuplicates(t)
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 nil value. (For arrays containing nil 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 {5, 4, 4, 3, 4, 2, 2, 1} removeDuplicates will return {5, 4, 3, 2, 1}
numKeys
TableTools.numKeys(t)
Takes a table ''t'' 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 {'foo', nil, 'bar', 'baz', a = 'b'}, numKeys will return {1, 3, 4}.
affixNums
TableTools.affixNums(t, prefix, suffix)
Takes a table ''t'' and returns an array containing the numbers of keys with the optional prefix ''prefix'' and the optional suffix ''suffix''. For example, for the table {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix 'a', affixNums will return {1, 3, 6}. All characters in ''prefix'' and ''suffix'' are interpreted literally.
numData
TableTools.numData(t, compress)
Given a table with keys like "foo1", "bar1", "foo2", and "baz2", returns a table of subtables in the format { [1] = {foo = 'text', bar = 'text'}, [2] = {foo = 'text', baz = 'text'} }. 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
TableTools.compressSparseArray(t)
Takes an array ''t'' 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 {1, nil, foo = 'bar', 3, 2}, compressSparseArray will return {1, 3, 2}.
sparseIpairs
TableTools.sparseIpairs(t)
This is an iterator function for traversing a sparse array ''t''. It is similar to ipairs, but will continue to iterate until the highest numerical key, whereas ipairs may stop after the first nil value. Any keys that are not positive integers are ignored.
Usually sparseIpairs is used in a generic for loop.
for i, v in TableTools.sparseIpairs(t) do -- code block end
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
TableTools.size(t)
Finds the size of a key/value pair table. For example, for the table {foo = 'foo', bar = 'bar'}, size will return 2. 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
TableTools.keysToList(t, keySort)
Returns a list of the keys in a table, sorted using either a default comparison function or a custom keySort function, which follows the same rules as the comp function supplied to table.sort.
sortedPairs
TableTools.sortedPairs(t, keySort)
Iterates through a table, with the keys sorted using the keysToList function. If there are only numerical keys, sparseIpairs is probably more efficient.
isArray
TableTools.isArray(t)
Returns true if all keys in the table are consecutive integers starting at 1.
listToSet
TableTools.listToSet(arr)
Creates a set from the array part of the table arr. Indexing the set by any of the values in arr returns true.
local set = TableTools.listToSet { "a", "b", "c" }
assert(set["a"] == true)
invert
TableTools.invert(t)
Transposes the keys and values in an array. For example, invert{ "a", "b", "c" } yields { a = 1, b = 2, c = 3 }.
deepCopy
TableTools.deepCopy(orig, noMetatable, alreadySeen)
Creates a copy of the table orig. As with mw.clone, all values that are not functions are duplicated and the identity of tables is preserved. If noMetatable is true, then the metatable (if any) is not copied. Can copy tables loaded with mw.loadData.
Similar to mw.clone, but mw.clone cannot copy tables loaded with mw.loadData and does not allow metatables not to be copied.
sparseConcat
TableTools.sparseConcat(t, sep)
Concatenates all values in the table that are indexed by a positive integer, in order.
length
TableTools.length(t)
Returns the length of a table, or the first integer key n counting from 0 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 and on frame.args. Both use a metatable such that #mw.loadData("module:...") and #frame.args don’t work correctly. For other tables, use #.
inArray
TableTools.inArray(arr, valueToFind)
Returns true if valueToFind is a member of the array arr, and false otherwise.