NAME¶
lassign - Assign list elements to variables
SYNOPSIS¶
lassign list ?varName ...?
DESCRIPTION¶
This command treats the value list as a list and assigns successive
elements from that list to the variables given by the varName arguments
in order. If there are more variable names than list elements, the remaining
variables are set to the empty string. If there are more list elements than
variables, a list of unassigned elements is returned.
EXAMPLES¶
An illustration of how multiple assignment works, and what happens when there
are either too few or too many elements.
lassign {a b c} x y z ;# Empty return
puts $x ;# Prints "a"
puts $y ;# Prints "b"
puts $z ;# Prints "c"
lassign {d e} x y z ;# Empty return
puts $x ;# Prints "d"
puts $y ;# Prints "e"
puts $z ;# Prints ""
lassign {f g h i} x y ;# Returns "h i"
puts $x ;# Prints "f"
puts $y ;# Prints "g"
The lassign command has other uses. It can be used to
create the analogue of the “shift” command in many shell
languages like this:
set ::argv [lassign $::argv argumentToReadOff]
SEE ALSO¶
lindex(3tcl), list(3tcl), lrange(3tcl), lset(3tcl), set(3tcl)
KEYWORDS¶
assign, element, list, multiple, set, variable
