1unset(n) Tcl Built-In Commands unset(n)
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8 unset - Delete variables
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11 unset ?-nocomplain? ?--? ?name name name ...?
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16 This command removes one or more variables. Each name is a variable
17 name, specified in any of the ways acceptable to the set command. If a
18 name refers to an element of an array then that element is removed
19 without affecting the rest of the array. If a name consists of an
20 array name with no parenthesized index, then the entire array is
21 deleted. The unset command returns an empty string as result. If │
22 -nocomplain is specified as the first argument, any possible errors are │
23 suppressed. The option may not be abbreviated, in order to disam‐ │
24 biguate it from possible variable names. The option -- indicates the │
25 end of the options, and should be used if you wish to remove a variable │
26 with the same name as any of the options. If an error occurs, any
27 variables after the named one causing the error not deleted. An error
28 can occur when the named variable doesn't exist, or the name refers to
29 an array element but the variable is a scalar, or the name refers to a
30 variable in a non-existent namespace.
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33 Create an array containing a mapping from some numbers to their squares
34 and remove the array elements for non-prime numbers:
35 array set squares {
36 1 1 6 36
37 2 4 7 49
38 3 9 8 64
39 4 16 9 81
40 5 25 10 100
41 }
42 puts "The squares are:"
44 parray squares
45 unset [22msquares(1) squares(4) squares(6)
47 unset [22msquares(8) squares(9) squares(10)
48 puts "The prime squares are:"
50 parray squares
51
54 set(n), trace(n), upvar(n)
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58 remove, variable
59Tcl 8.4 unset(n)