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Tcl – Lists ”; Previous Next List is one of the basic data-type available in Tcl. It is used for representing an ordered collection of items. It can include different types of items in the same list. Further, a list can contain another list. An important thing that needs to be noted is that these lists are represented as strings completely and processed to form individual items when required. So, avoid large lists and in such cases; use array. Creating a List The general syntax for list is given below − set listName { item1 item2 item3 .. itemn } # or set listName [list item1 item2 item3] # or set listName [split “items separated by a character” split_character] Some examples are given below − Live Demo #!/usr/bin/tclsh set colorList1 {red green blue} set colorList2 [list red green blue] set colorList3 [split “red_green_blue” _] puts $colorList1 puts $colorList2 puts $colorList3 When the above code is executed, it produces the following result − red green blue red green blue red green blue Appending Item to a List The syntax for appending item to a list is given below − append listName split_character value # or lappend listName value Some examples are given below − Live Demo #!/usr/bin/tclsh set var orange append var ” ” “blue” lappend var “red” lappend var “green” puts $var When the above code is executed, it produces the following result − orange blue red green Length of List The syntax for length of list is given below − llength listName Example for length of list is given below − Live Demo #!/usr/bin/tclsh set var {orange blue red green} puts [llength $var] When the above code is executed, it produces the following result − 4 List Item at Index The syntax for selecting list item at specific index is given below − lindex listname index Example for list item at index is given below − Live Demo #!/usr/bin/tclsh set var {orange blue red green} puts [lindex $var 1] When the above code is executed, it produces the following result − blue Insert Item at Index The syntax for inserting list items at specific index is given below. linsert listname index value1 value2..valuen Example for inserting list item at specific index is given below. Live Demo #!/usr/bin/tclsh set var {orange blue red green} set var [linsert $var 3 black white] puts $var When the above code is executed, it produces the following result − orange blue red black white green Replace Items at Indices The syntax for replacing list items at specific indices is given below − lreplace listname firstindex lastindex value1 value2..valuen Example for replacing list items at specific indices is given below. Live Demo #!/usr/bin/tclsh set var {orange blue red green} set var [lreplace $var 2 3 black white] puts $var When the above code is executed, it produces the following result − orange blue black white Set Item at Index The syntax for setting list item at specific index is given below − lset listname index value Example for setting list item at specific index is given below − Live Demo #!/usr/bin/tclsh set var {orange blue red green} lset var 0 black puts $var When the above code is executed, it produces the following result − black blue red green Transform List to Variables The syntax for copying values to variables is given below − lassign listname variable1 variable2.. variablen Example for transforming list into variables is given below − Live Demo #!/usr/bin/tclsh set var {orange blue red green} lassign $var colour1 colour2 puts $colour1 puts $colour2 When the above code is executed, it produces the following result − orange blue Sorting a List The syntax for sorting a list is given below − lsort listname An example for sorting a list is given below − Live Demo #!/usr/bin/tclsh set var {orange blue red green} set var [lsort $var] puts $var When the above code is executed, it produces the following result − blue green orange red Print Page Previous Next Advertisements ”;