1lassign(n) Tcl Built-In Commands lassign(n)
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8 lassign - Assign list elements to variables
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11 lassign list ?varName ...?
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15 This command treats the value list as a list and assigns successive
16 elements from that list to the variables given by the varName arguments
17 in order. If there are more variable names than list elements, the
18 remaining variables are set to the empty string. If there are more
19 list elements than variables, a list of unassigned elements is
20 returned.
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23 An illustration of how multiple assignment works, and what happens when
24 there are either too few or too many elements.
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26 lassign {a b c} x y z ;# Empty return
27 puts $x ;# Prints "a"
28 puts $y ;# Prints "b"
29 puts $z ;# Prints "c"
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31 lassign {d e} x y z ;# Empty return
32 puts $x ;# Prints "d"
33 puts $y ;# Prints "e"
34 puts $z ;# Prints ""
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36 lassign {f g h i} x y ;# Returns "h i"
37 puts $x ;# Prints "f"
38 puts $y ;# Prints "g"
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40 The lassign command has other uses. It can be used to create the ana‐
41 logue of the “shift” command in many shell languages like this:
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43 set ::argv [lassign $::argv argumentToReadOff]
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46 lindex(n), list(n), lrange(n), lset(n), set(n)
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49 assign, element, list, multiple, set, variable
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53Tcl 8.5 lassign(n)