Tcl Built-In Commands - lassign manual page

### NAME

lassign - Assign list elements to variables

### SYNOPSIS

lassign list varName ?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, list, lset, set

### KEYWORDS

assign, element, list, multiple, set, variable

    Copyright © 1992-1999 Karl Lehenbauer & Mark Diekhans
    Copyright © 2004 Donal K. Fellows
    Copyright © 1995-1997 Roger E. Critchlow Jr.