lindex man page on SmartOS

Man page or keyword search:  
man Server   16655 pages
apropos Keyword Search (all sections)
Output format
SmartOS logo
[printable version]

lindex(n)		     Tcl Built-In Commands		     lindex(n)


       lindex - Retrieve an element from a list

       lindex list ?index ...?

       The  lindex command accepts a parameter, list, which it treats as a Tcl
       list. It also accepts zero or more indices into the list.  The  indices
       may  be	presented either consecutively on the command line, or grouped
       in a Tcl list and presented as a single argument.

       If no indices are presented, the command takes the form:

	      lindex list


	      lindex list {}

       In this case, the return value of lindex is simply  the	value  of  the
       list parameter.

       When presented with a single index, the lindex command treats list as a
       Tcl list and returns the index'th element from  it  (0  refers  to  the
       first element of the list).  In extracting the element, lindex observes
       the same rules concerning braces and quotes and backslashes as the  Tcl
       command interpreter; however, variable substitution and command substi‐
       tution do not occur.  If index is negative or greater than or equal  to
       the number of elements in value, then an empty string is returned.  The
       interpretation of each simple index value is the same as for  the  com‐
       mand string index, supporting simple index arithmetic and indices rela‐
       tive to the end of the list.

       If additional index arguments are supplied, then each argument is  used
       in  turn	 to  select  an	 element from the previous indexing operation,
       allowing the script to select elements from sublists.  The command,

	      lindex $a 1 2 3


	      lindex $a {1 2 3}

       is synonymous with

	      lindex [lindex [lindex $a 1] 2] 3

       Lists can be indexed into from either end:

	      lindex {a b c} 0
		    → a
	      lindex {a b c} 2
		    → c
	      lindex {a b c} end
		    → c
	      lindex {a b c} end-1
		    → b

       Lists or sequences of indices allow selection into lists of lists:

	      lindex {a b c}
		    → a b c
	      lindex {a b c} {}
		    → a b c
	      lindex {{a b c} {d e f} {g h i}} 2 1
		    → h
	      lindex {{a b c} {d e f} {g h i}} {2 1}
		    → h
	      lindex {{{a b} {c d}} {{e f} {g h}}} 1 1 0
		    → g
	      lindex {{{a b} {c d}} {{e f} {g h}}} {1 1 0}
		    → g

       List indices may also perform limited computation, adding or  subtract‐
       ing fixed amounts from other indices:

	      set idx 1
	      lindex {a b c d e f} $idx+2
		    → d
	      set idx 3
	      lindex {a b c d e f} $idx+2
		    → f

       list(n),	  lappend(n),  linsert(n),  llength(n),	 lsearch(n),  lset(n),
       lsort(n), lrange(n), lreplace(n), string(n)

       element, index, list

Tcl				      8.4			     lindex(n)

List of man pages available for SmartOS

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net