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In some programming languages (including Ada, Perl, Ruby, Apache Groovy, Kotlin, Haskell, and Pascal), a shortened two-dot ellipsis is used to represent a range of values given two endpoints; for example, to iterate through a list of integers between 1 and 100 inclusive in Perl: foreach (1..100)
For example, to perform an element by element sum of two arrays, a and b to produce a third c, it is only necessary to write c = a + b In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine.
A table is a sequence, optionally supplemented by named keys: digit["two"]="2". Several table functions like table.concat will only work with the numbered values and ignore named keys. The metatable offers a large, optional set of methods for altering table behavior. For example, you can define a table to be callable like a function.
The indices are one-based (meaning the first is number one), inclusive (meaning the indices you specify are included), and may be negative to count from the other end. For example, {{#invoke:string|sub|12345678|2|-3}} → 23456. Not all the legacy substring templates use this numbering scheme, so check the documentation of unfamiliar templates.
Lua functions may pass varargs to other functions the same way as other values using the return keyword. tables can be passed into variadic functions by using, in Lua version 5.2 or higher [9] table.unpack, or Lua 5.1 or lower [10] unpack. Varargs can be used as a table by constructing a table with the vararg as a value.
One discrete problem that is expensive to solve on many computers is that of counting the number of bits that are set to 1 in a (binary) number, sometimes called the population function. For example, the decimal number "37" is "00100101" in binary, so it contains three bits that are set to binary "1". [7]: 282
A label is an explicit name or number assigned to a fixed position within the source code, and which may be referenced by control flow statements appearing elsewhere in the source code. A label marks a position within source code and has no other effect. Line numbers are an alternative to a named label used in some languages (such as BASIC).
The C API also provides some special tables, located at various "pseudo-indices" in the Lua stack. At LUA_GLOBALSINDEX prior to Lua 5.2 [21] is the globals table, _G from within Lua, which is the main namespace. There is also a registry located at LUA_REGISTRYINDEX where C programs can store Lua values for later retrieval.