array(n) Tcl Built-In Commands array(n)
NAME
array - Manipulate array variables
SYNOPSIS
array option arrayName ?arg arg ...?
DESCRIPTION
This command performs one of several operations on the variable given
by arrayName. Unless otherwise specified for individual commands
below, arrayName must be the name of an existing array variable. The
option argument determines what action is carried out by the command.
The legal options (which may be abbreviated) are:
array anymore arrayName searchId
Returns 1 if there are any more elements left to be processed in
an array search, 0 if all elements have already been returned.
SearchId indicates which search on arrayName to check, and must
have been the return value from a previous invocation of array
startsearch. This option is particularly useful if an array has
an element with an empty name, since the return value from array
nextelement will not indicate whether the search has been com-
pleted.
array donesearch arrayName searchId
This command terminates an array search and destroys all the
state associated with that search. SearchId indicates which
search on arrayName to destroy, and must have been the return
value from a previous invocation of array startsearch. Returns
an empty string.
array exists arrayName
Returns 1 if arrayName is an array variable, 0 if there is no
variable by that name or if it is a scalar variable.
array get arrayName ?pattern?
Returns a list containing pairs of elements. The first element
in each pair is the name of an element in arrayName and the sec-
ond element of each pair is the value of the array element. The
order of the pairs is undefined. If pattern is not specified,
then all of the elements of the array are included in the
result. If pattern is specified, then only those elements whose
names match pattern (using the matching rules of string match)
are included. If arrayName is not the name of an array vari-
able, or if the array contains no elements, then an empty list
is returned. If traces on the array modify the list of ele-
ments, the elements returned are those that exist both before
and after the call to array get.
array names arrayName ?mode? ?pattern?
Returns a list containing the names of all of the elements in
the array that match pattern. Mode may be one of -exact, -glob,
or -regexp. If specified, mode designates which matching rules
to use to match pattern against the names of the elements in the
array. If not specified, mode defaults to -glob. See the docu-
mentation for string match for information on glob style match-
ing, and the documentation for regexp for information on regexp
matching. If pattern is omitted then the command returns all of
the element names in the array. If there are no (matching) ele-
ments in the array, or if arrayName is not the name of an array
variable, then an empty string is returned.
array nextelement arrayName searchId
Returns the name of the next element in arrayName, or an empty
string if all elements of arrayName have already been returned
in this search. The searchId argument identifies the search,
and must have been the return value of an array startsearch com-
mand. Warning: if elements are added to or deleted from the
array, then all searches are automatically terminated just as if
array donesearch had been invoked; this will cause array nex-
telement operations to fail for those searches.
array set arrayName list
Sets the values of one or more elements in arrayName. list must
have a form like that returned by array get, consisting of an
even number of elements. Each odd-numbered element in list is
treated as an element name within arrayName, and the following
element in list is used as a new value for that array element.
If the variable arrayName does not already exist and list is
empty, arrayName is created with an empty array value.
array size arrayName
Returns a decimal string giving the number of elements in the
array. If arrayName is not the name of an array then 0 is
returned.
array startsearch arrayName
This command initializes an element-by-element search through
the array given by arrayName, such that invocations of the array
nextelement command will return the names of the individual ele-
ments in the array. When the search has been completed, the
array donesearch command should be invoked. The return value is
a search identifier that must be used in array nextelement and
array donesearch commands; it allows multiple searches to be
underway simultaneously for the same array. It is currently
more efficient and easier to use either the array get or array
names, together with foreach, to iterate over all but very large
arrays. See the examples below for how to do this.
array statistics arrayName
Returns statistics about the distribution of data within the
hashtable that represents the array. This information includes
the number of entries in the table, the number of buckets, and
the utilization of the buckets.
array unset arrayName ?pattern?
Unsets all of the elements in the array that match pattern
(using the matching rules of string match). If arrayName is not
the name of an array variable or there are no matching elements
in the array, no error will be raised. If pattern is omitted
and arrayName is an array variable, then the command unsets the
entire array. The command always returns an empty string.
EXAMPLES
array set colorcount {
red 1
green 5
blue 4
white 9 }
foreach {color count} [array get colorcount] {
puts "Color: $color Count: $count" }
-> Color: blue Count: 4
Color: white Count: 9
Color: green Count: 5
Color: red Count: 1
foreach color [array names colorcount] {
puts "Color: $color Count: $colorcount($color)" }
-> Color: blue Count: 4
Color: white Count: 9
Color: green Count: 5
Color: red Count: 1
foreach color [lsort [array names colorcount]] {
puts "Color: $color Count: $colorcount($color)" }
-> Color: blue Count: 4
Color: green Count: 5
Color: red Count: 1
Color: white Count: 9
array statistics colorcount
-> 4 entries in table, 4 buckets
number of buckets with 0 entries: 1
number of buckets with 1 entries: 2
number of buckets with 2 entries: 1
number of buckets with 3 entries: 0
number of buckets with 4 entries: 0
number of buckets with 5 entries: 0
number of buckets with 6 entries: 0
number of buckets with 7 entries: 0
number of buckets with 8 entries: 0
number of buckets with 9 entries: 0
number of buckets with 10 or more entries: 0
average search distance for entry: 1.2
SEE ALSO
list(n), string(n), variable(n), trace(n), foreach(n)
KEYWORDS
array, element names, search
Tcl 8.3 array(n)
tcl 8.6.0 - Generated Mon Jan 7 18:59:10 CST 2013