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An array is a systematic arrangement of a group of elements using indices. The syntax for the conventional array is shown below.
set ArrayName(Index) value
An example for creating simple array is shown below.
#!/usr/bin/tclsh set languages(0) Tcl set languages(1) "C Language" puts $languages(0) puts $languages(1)
When the above code is executed, it produces the following result −
Tcl C Language
Size of Array
The syntax for calculating size array is shown below.
[array size variablename]
An example for printing the size is shown below.
#!/usr/bin/tclsh set languages(0) Tcl set languages(1) "C Language" puts [array size languages]
When the above code is executed, it produces the following result −
2
Array Iteration
Though, array indices can be non-continuous like values specified for index 1 then index 10 and so on. But, in case they are continuous, we can use array iteration to access elements of the array. A simple array iteration for printing elements of the array is shown below.
#!/usr/bin/tclsh
set languages(0) Tcl
set languages(1) "C Language"
for { set index 0 } { $index < [array size languages] } { incr index } {
puts "languages($index) : $languages($index)"
}
When the above code is executed, it produces the following result −
languages(0) : Tcl languages(1) : C Language
Associative Arrays
In Tcl, all arrays by nature are associative. Arrays are stored and retrieved without any specific order. Associative arrays have an index that is not necessarily a number, and can be sparsely populated. A simple example for associative array with non-number indices is shown below.
#!/usr/bin/tclsh set personA(Name) "Dave" set personA(Age) 14 puts $personA(Name) puts $personA(Age)
When the above code is executed, it produces the following result −
Dave 14
Indices of Array
The syntax for retrieving indices of array is shown below.
[array names variablename]
An example for printing the size is shown below.
#!/usr/bin/tclsh set personA(Name) "Dave" set personA(Age) 14 puts [array names personA]
When the above code is executed, it produces the following result −
Age Name
Iteration of Associative Array
You can use the indices of array to iterate through the associative array. An example is shown below.
#!/usr/bin/tclsh
set personA(Name) "Dave"
set personA(Age) 14
foreach index [array names personA] {
puts "personA($index): $personA($index)"
}
When the above code is executed, it produces the following result −
personA(Age): 14 personA(Name): Dave
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