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lappend(n) [opendarwin man page]

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


lappend - Append list elements onto a variable SYNOPSIS
lappend varName ?value value value ...? _________________________________________________________________ DESCRIPTION
This command treats the variable given by varName as a list and appends each of the value arguments to that list as a separate element, with spaces between elements. If varName doesn't exist, it is created as a list with elements given by the value arguments. Lappend is similar to append except that the values are appended as list elements rather than raw text. This command provides a relatively efficient way to build up large lists. For example, ``lappend a $b'' is much more efficient than ``set a [concat $a [list $b]]'' when $a is long. SEE ALSO
list(n), lindex(n), linsert(n), llength(n), lset(n) lsort(n), lrange(n) | KEYWORDS
append, element, list, variable Tcl lappend(n)

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


lset - Change an element in a list SYNOPSIS
lset varName ?index...? newValue _________________________________________________________________ DESCRIPTION
The lset command accepts a parameter, varName, which it interprets as the name of a variable containing 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 pre- sented as a single argument. Finally, it accepts a new value for an element of varName. If no indices are presented, the command takes the form: lset varName newValue or lset varName {} newValue In this case, newValue replaces the old value of the variable varName. When presented with a single index, the lset command treats the content of the varName variable as a Tcl list. It addresses the index'th element in it (0 refers to the first element of the list). When interpreting the list, lset observes the same rules concerning braces and quotes and backslashes as the Tcl command interpreter; however, variable substitution and command substitution do not occur. The command constructs a new list in which the designated element is replaced with newValue. This new list is stored in the variable varName, and is also the return value from the lset command. If index is negative or greater than or equal to the number of elements in $varName, then an error occurs. The interpretation of each simple index value is the same as for the command string index, supporting simple index arithmetic and indices | relative to the end of the list. If additional index arguments are supplied, then each argument is used in turn to address an element within a sublist designated by the previous indexing operation, allowing the script to alter elements in sublists. The command, lset a 1 2 newValue or lset a {1 2} newValue replaces element 2 of sublist 1 with newValue. The integer appearing in each index argument must be greater than or equal to zero. The integer appearing in each index argument must be strictly less than the length of the corresponding list. In other words, the lset command cannot change the size of a list. If an index is outside the permitted range, an error is reported. EXAMPLES
In each of these examples, the initial value of x is: set x [list [list a b c] [list d e f] [list g h i]] -> {a b c} {d e f} {g h i} The indicated return value also becomes the new value of x (except in the last case, which is an error which leaves the value of x unchanged.) lset x {j k l} -> j k l lset x {} {j k l} -> j k l lset x 0 j -> j {d e f} {g h i} lset x 2 j -> {a b c} {d e f} j lset x end j -> {a b c} {d e f} j lset x end-1 j -> {a b c} j {g h i} lset x 2 1 j -> {a b c} {d e f} {g j i} lset x {2 1} j -> {a b c} {d e f} {g j i} lset x {2 3} j -> list index out of range In the following examples, the initial value of x is: set x [list [list [list a b] [list c d]] [list [list e f] [list g h]]] -> {{a b} {c d}} {{e f} {g h}} The indicated return value also becomes the new value of x. lset x 1 1 0 j -> {{a b} {c d}} {{e f} {j h}} lset x {1 1 0} j -> {{a b} {c d}} {{e f} {j h}} SEE ALSO
list(n), lappend(n), lindex(n), linsert(n), llength(n), lsearch(n), lsort(n), lrange(n), lreplace(n), string(n) | KEYWORDS
element, index, list, replace, set Tcl 8.4 lset(n)
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