1lindex(n) Tcl Built-In Commands lindex(n)
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8 lindex - Retrieve an element from a list
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11 lindex list ?index...?
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15 The lindex command accepts a parameter, list, which it treats as a Tcl │
16 list. It also accepts zero or more indices into the list. The indices │
17 may be presented either consecutively on the command line, or grouped │
18 in a Tcl list and presented as a single argument. │
19 If no indices are presented, the command takes the form: │
21 lindex list │
22 or │
23 lindex list {} │
24 In this case, the return value of lindex is simply the value of the │
25 list parameter. │
26 When presented with a single index, the lindex command treats list as a │
28 Tcl list and returns the index'th element from it (0 refers to the
29 first element of the list). In extracting the element, lindex observes
30 the same rules concerning braces and quotes and backslashes as the Tcl
31 command interpreter; however, variable substitution and command substi‐
32 tution do not occur. If index is negative or greater than or equal to
33 the number of elements in value, then an empty string is returned. If
34 index has the value end, it refers to the last element in the list, and
35 end-integer refers to the last element in the list minus the specified
36 integer offset.
37 If additional index arguments are supplied, then each argument is used │
39 in turn to select an element from the previous indexing operation, │
40 allowing the script to select elements from sublists. The command, │
41 lindex $a 1 2 3 │
42 or │
43 lindex $a {1 2 3} │
44 is synonymous with │
45 lindex [lindex [lindex $a 1] 2] 3 │
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48 lindex {a b c} => a b c │
49 lindex {a b c} {} => a b c │
50 lindex {a b c} 0 => a │
51 lindex {a b c} 2 => c │
52 lindex {a b c} end => c │
53 lindex {a b c} end-1 => b │
54 lindex {{a b c} {d e f} {g h i}} 2 1 => h │
55 lindex {{a b c} {d e f} {g h i}} {2 1} => h │
56 lindex {{{a b} {c d}} {{e f} {g h}}} 1 1 0 => g │
57 lindex {{{a b} {c d}} {{e f} {g h}}} {1 1 0} => g │
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60 list(n), lappend(n), linsert(n), llength(n), lsearch(n), lset(n), │
61 lsort(n), lrange(n), lreplace(n)
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65 element, index, list
66Tcl 8.4 lindex(n)