array - Manipulate array variables

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:

arrayanymorearrayNamesearchId
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 arraystartsearch. This option is
particularly useful if an array has an element with an empty name, since the return value from
arraynextelement will not indicate whether the search has been completed.

arraydefaultsubcommandarrayNameargs...
Manages the default value of the array. Arrays initially have no default value, but this command 2
allows you to set one; the default value will be returned when reading from an element of the 2
array arrayName if the read would otherwise result in an error. Note that this may cause the 2
append, dict, incr and lappend commands to change their behavior in relation to non-existing array 2
elements. 2

The subcommand argument controls what exact operation will be performed on the default value of 2
arrayName. Supported subcommands are:

arraydefaultexistsarrayName
This returns a boolean value indicating whether a default value has been set for the array 2
arrayName. Returns a false value if arrayName does not exist. Raises an error if arrayName 2
is an existing variable that is not an array.

arraydefaultgetarrayName
This returns the current default value for the array arrayName. Raises an error if 2
arrayName is an existing variable that is not an array, or if arrayName is an array without 2
a default value.

arraydefaultsetarrayNamevalue
This sets the default value for the array arrayName to value. Returns the empty string. 2
Raises an error if arrayName is an existing variable that is not an array, or if arrayName 2
is an illegal name for an array. If arrayName does not currently exist, it is created as an 2
empty array as well as having its default value set.

arraydefaultunsetarrayName
This removes the default value for the array arrayName and returns the empty string. Does 2
nothing if arrayName does not have a default value. Raises an error if arrayName is an 2
existing variable that is not an array.

arraydonesearcharrayNamesearchId
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 arraystartsearch. Returns an empty string.

arrayexistsarrayName
Returns 1 if arrayName is an array variable, 0 if there is no variable by that name or if it is a
scalar variable.

arrayfor{keyVariablevalueVariable}arrayNamebody
The first argument is a two element list of variable names for the key and value of each entry in
the array. The second argument is the array name to iterate over. The third argument is the body
to execute for each key and value returned. The ordering of the returned keys is undefined. If
an array element is deleted or a new array element is inserted during the arrayfor process, the
command will terminate with an error.

arraygetarrayName ?pattern?
Returns a list containing pairs of elements. The first element in each pair is the name of an
element in arrayName and the second 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 stringmatch) are included. If arrayName is not the
name of an array variable, or if the array contains no elements, then an empty list is returned.
If traces on the array modify the list of elements, the elements returned are those that exist
both before and after the call to arrayget.

arraynamesarrayName ?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 documentation for stringmatch for information on glob style matching,
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) elements in
the array, or if arrayName is not the name of an array variable, then an empty string is returned.

arraynextelementarrayNamesearchId
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 arraystartsearch command. Warning: if elements are added to or
deleted from the array, then all searches are automatically terminated just as if arraydonesearch
had been invoked; this will cause arraynextelement operations to fail for those searches.

arraysetarrayNamelist
Sets the values of one or more elements in arrayName. list must have a form like that returned by
arrayget, 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.

arraysizearrayName
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.

arraystartsearcharrayName
This command initializes an element-by-element search through the array given by arrayName, such
that invocations of the arraynextelement command will return the names of the individual elements
in the array. When the search has been completed, the arraydonesearch command should be invoked.
The return value is a search identifier that must be used in arraynextelement and arraydonesearch commands; it allows multiple searches to be underway simultaneously for the same array.
It is currently more efficient and easier to use either the arrayget or arraynames, together
with foreach, to iterate over all but very large arrays. See the examples below for how to do
this.

arraystatisticsarrayName
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.

arrayunsetarrayName ?pattern?
Unsets all of the elements in the array that match pattern (using the matching rules of stringmatch). 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

arrayset colorcount {
                  red   1
                  green 5
                  blue  4
                  white 9
              }

              foreach {color count} [arrayget colorcount] {
                  puts "Color: $color Count: $count"
              }
                → Color: blue Count: 4
                  Color: white Count: 9
                  Color: green Count: 5
                  Color: red Count: 1

              foreach color [arraynames 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 [arraynames colorcount]] {
                  puts "Color: $color Count: $colorcount($color)"
              }
                → Color: blue Count: 4
                  Color: green Count: 5
                  Color: red Count: 1
                  Color: white Count: 9

              arraystatistics 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

Keywords

       array, element names, search

Tcl                                                    9.0                                           array(3tcl)

Name

       array - Manipulate array variables

Synopsis

arrayoptionarrayName ?argarg...?
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