array
array
NAMESYNOPSIS
DESCRIPTION
EXAMPLES
SEE ALSO
KEYWORDS
___________________________
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 completed.
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 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 string match) 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 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 documentation for string match 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.
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 command. 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 nextelement 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 elements 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(3), variable(n), trace(3ncurses), foreach(n)
KEYWORDS
array, element names, search
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
