Difference between revisions of "Next"
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=== Description === | === Description === | ||
| − | Allows a program to traverse all fields of a table. Its first argument is a table and its second argument is an index in this table. next returns the next index of the table and its associated value. | + | Allows a program to traverse all fields of a table. |
| + | <syntaxhighlight lang="lua"> | ||
| + | next(table,index) | ||
| + | </syntaxhighlight> | ||
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| + | Its first argument is a table and its second argument is an index in this table. ''next'' returns the next index of the table and its associated value. | ||
| + | |||
| + | *when called with nil as its second argument, ''next'' returns an initial index and its associated value | ||
| + | *when called with the last index, or with nil in an empty table, ''next'' returns nil | ||
| + | *if the second argument is absent, then it is interpreted as nil. In particular, you can use ''next''(t) to check whether a table is empty. | ||
| − | The order in which the indices are enumerated is not specified, even for numeric indices. | + | The order in which the indices are enumerated is not specified, even for numeric indices. To traverse a table in numeric order, use a numerical for or the [[ipairs]] function. |
| − | The behavior of next is undefined if, during the traversal, you assign any value to a non-existent field in the table. You may however modify existing fields | + | The behavior of next is undefined if, during the traversal, you assign any value to a non-existent field in the table. You may however modify existing fields, in particular, you may clear existing fields. |
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=== Parameters === | === Parameters === | ||
Latest revision as of 14:30, 13 July 2023
Available since: Gideros 2011.6
Class: (global)
Description
Allows a program to traverse all fields of a table.
next(table,index)
Its first argument is a table and its second argument is an index in this table. next returns the next index of the table and its associated value.
- when called with nil as its second argument, next returns an initial index and its associated value
- when called with the last index, or with nil in an empty table, next returns nil
- if the second argument is absent, then it is interpreted as nil. In particular, you can use next(t) to check whether a table is empty.
The order in which the indices are enumerated is not specified, even for numeric indices. To traverse a table in numeric order, use a numerical for or the ipairs function.
The behavior of next is undefined if, during the traversal, you assign any value to a non-existent field in the table. You may however modify existing fields, in particular, you may clear existing fields.
Parameters
table: (table) table to traverse
index: (number) previous table index optional
