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collection/
mgcohashtable__define.pro
collection
includes main-level programA hash table which can hash any kind of IDL variables. To hash objects, simply make sure each object implements the hashCode method. See the help for the calcHashCode method for details.
Examples
Try the main-level example program at the end of this file:
IDL> .run mgcohashtable__define
Class description for mgcohashtable
Inheritance
Properties
- count get
- array_size init
- key_type get init
- value_example init
- key_example init
- value_type get init
Author information
- Author
Michael D. Galloy
Routines
result = mgcohashtable::_overloadBracketsRightSide(isRange, ss1, ss2, ss3, ss4, ss5, ss6, ss7, ss8)Allows hash table access with brackets.
mgcohashtable::_overloadBracketsLeftSide, objref, value, isRange, ss1, ss2, ss3, ss4, ss5, ss6, ss7, ss8Allows setting values of the array list by array index.
result = mgcohashtable::_overloadPlus(left, right)Concatenate two hash tables.
mgcohashtable::_findKeyPos, key [, hcode] [, keyIndex]Helper method to find the position of a key.
result = mgcohashtable::_findNextKey(key [, /done])Finds the next key in the hash, if present.
result = mgcohashtable::_overloadForeach(value [, key])Allows an array list to be used in a FOREACH loop.
result = mgcohashtable::_overloadPrint()Returns the elements to print.
result = mgcohashtable::_overloadHelp(varname)Returns a string describing the array list.
result = mgcohashtable::_overloadSize()Returns the number of elements in the array list.
mgcohashtable::getProperty, key_type=key_type, value_type=value_type, count=countmgcohashtable::print [, lun]Prints keys and values to a given LUN.
result = mgcohashtable::keys( [count=integral])Returns an array of the keys of the hash table.
result = mgcohashtable::values( [count=integral])Returns an array of the values of the hash table.
result = mgcohashtable::_calcHashCode(key)Calculates the hash code of the given key.
result = mgcohashtable::get(key [, default=any] [, /found])Finds the value associated with the given key.
result = mgcohashtable::setdefault(key [, default=any])Finds the value associated with the given key, but sets the value for the key to default if the key is not found.
mgcohashtable::remove [, key] [, /all] [, /found]Removes the value associated with the given key.
mgcohashtable::update, hashtableAdds all the keys of hashtable to the this hash table (replacing values in this hash table if they are in present in hashtable).
mgcohashtable::put, key, value [, /found]Puts the key-value pair into the hash table or updates the value for the key if it is already in the hash table.
result = mgcohashtable::count()Find the number of key-value pairs in the hash table
result = mgcohashtable::isEmpty()Determines if the hash table is empty.
mgcohashtable::cleanupFrees hash table resources, but the resources contained by the hash table.
result = mgcohashtable::init( [array_size=integral], key_type=0-15, value_type=0-15, key_example=key type, value_example=value type)Create a hash table.
mgcohashtable__defineHash table implementation.
Routine details
top source mgcohashtable::_overloadBracketsRightSide
result = mgcohashtable::_overloadBracketsRightSide(isRange, ss1, ss2, ss3, ss4, ss5, ss6, ss7, ss8)
Allows hash table access with brackets.
Return value
elements of the same type as the array list
Parameters
- isRange
- ss1
- ss2
- ss3
- ss4
- ss5
- ss6
- ss7
- ss8
Examples
Try:
IDL> h = obj_new('MGcoHashTable', key_type=7, value_type=4)
IDL> h->put, 'Boulder', 72.0
IDL> print, h['Boulder']
72.0000
top source mgcohashtable::_overloadBracketsLeftSide
mgcohashtable::_overloadBracketsLeftSide, objref, value, isRange, ss1, ss2, ss3, ss4, ss5, ss6, ss7, ss8
Allows setting values of the array list by array index.
Parameters
- objref
- value
- isRange
- ss1
- ss2
- ss3
- ss4
- ss5
- ss6
- ss7
- ss8
Examples
Try:
IDL> h = obj_new('MGcoHashTable', key_type=7, value_type=4)
IDL> h['Boulder'] = 72.0
IDL> print, h['Boulder']
72.0000
top source mgcohashtable::_overloadPlus
result = mgcohashtable::_overloadPlus(left, right)
Concatenate two hash tables.
Return value
MGcoHashTable object
Parameters
- left
- right
top source mgcohashtable::_findKeyPos
mgcohashtable::_findKeyPos, key [, hcode] [, keyIndex]
Helper method to find the position of a key.
Parameters
- key in required type=key type
key to find position of
- hcode out optional type=long
hash code of the key
- keyIndex out optional type=long
index within list at hash code
top source mgcohashtable::_findNextKey
result = mgcohashtable::_findNextKey(key [, /done])
Finds the next key in the hash, if present.
Return value
next key, or -1L if last key
Parameters
- key in required type=key type or undefined
key to "increment"
Keywords
- done out optional type=boolean
set to a named variable to return if a next key is present, 0 if it is and if not, i.e., done
top source mgcohashtable::_overloadForeach
result = mgcohashtable::_overloadForeach(value [, key])
Allows an array list to be used in a FOREACH loop.
Return value
1 if there is an item to return, 0 if not
Parameters
- value out required type=list type
value to return as the loop
- key in out optional type=undefined/long
key is undefined for first element, otherwise the index of the last element returned
top source mgcohashtable::_overloadPrint
result = mgcohashtable::_overloadPrint()
Returns the elements to print. Called by PRINT to determine what should be displayed.
Return value
array of elements of the type of the array list
top source mgcohashtable::_overloadHelp
result = mgcohashtable::_overloadHelp(varname)
Returns a string describing the array list. Called by the HELP routine.
Return value
string
Parameters
- varname in required type=string
name of the variable to use when outputting help information
top source mgcohashtable::_overloadSize
result = mgcohashtable::_overloadSize()
Returns the number of elements in the array list. Called by SIZE to retrieve information about the size of the variable.
Return value
long
top source mgcohashtable::getProperty
mgcohashtable::getProperty, key_type=key_type, value_type=value_type, count=count
Keywords
- key_type
- value_type
- count
top source mgcohashtable::print
mgcohashtable::print [, lun]
Prints keys and values to a given LUN. Prints to STDOUT if LUN not given.
Parameters
- lun in optional type=LUN default=-1
logical unit number for output
top source mgcohashtable::keys
result = mgcohashtable::keys( [count=integral])
Returns an array of the keys of the hash table.
Return value
an array of the keys of the hash table or -1 if no keys
Keywords
- count out optional type=integral
number of keys in the hash table
top source mgcohashtable::values
result = mgcohashtable::values( [count=integral])
Returns an array of the values of the hash table.
Return value
an array of the values of the hash table or -1 if no values
Keywords
- count out optional type=integral
number of values in the hash table
top source mgcohashtable::_calcHashCode
result = mgcohashtable::_calcHashCode(key)
Calculates the hash code of the given key. The index of the array element the key's value will be stored in will be the hash code value MOD the array size.
If a hash tbale of object references is desired, then the objects should implement the hashCode method. This function should accept no parameters and return an unsigned long.
This method should not normally be called directly.
If the given default hash function is not doing well (use the _getHistogram method to find out how well it's spreading out the keys), subclass this class and implement a more appropriate hash function.
Return value
hash code (unsigned long integer); 0 if null pointer or object, undefined variable; or an object that does not implement hashCode
Parameters
- key in type=key type
key to find hash code of
top source mgcohashtable::get
result = mgcohashtable::get(key [, default=any] [, /found])
Finds the value associated with the given key.
Return value
the value of the associated key or -1L if not found
Parameters
- key in type=key type
key to look up
Keywords
- default in optional type=any
value to return if key is not present
- found out optional type=boolean
true if value found for given key
top source mgcohashtable::setdefault
result = mgcohashtable::setdefault(key [, default=any])
Finds the value associated with the given key, but sets the value for the
key to default if the key is not found.
Return value
the value of the associated key or -1L if not found
Parameters
- key in type=key type
key to look up
Keywords
- default in optional type=any
value to return and set the value for the key if key is not present
top source mgcohashtable::remove
mgcohashtable::remove [, key] [, /all] [, /found]
Removes the value associated with the given key.
Parameters
- key in optional type=key type
key to look up; not needed if ALL is set
Keywords
- all in optional type=boolean
set to remove all key-value pairs
- found out optional type=boolean
true if value found for given key
top source mgcohashtable::update
mgcohashtable::update, hashtable
Adds all the keys of hashtable to the this hash table (replacing values in
this hash table if they are in present in hashtable).
Parameters
- hashtable in required type=MGcoHashTable
MGcoHashTable to update this hash table with
top source mgcohashtable::put
mgcohashtable::put, key, value [, /found]
Puts the key-value pair into the hash table or updates the value for the key if it is already in the hash table.
Parameters
- key in required type=key type
key to place in the table
- value in required type=value type
value to place in the table
Keywords
- found out optional type=boolean
pass a named variable that is set to true if the key was already in the table and is updated
top source mgcohashtable::count
result = mgcohashtable::count()
Find the number of key-value pairs in the hash table
Return value
the number of key-value pairs in the hash table
top source mgcohashtable::isEmpty
result = mgcohashtable::isEmpty()
Determines if the hash table is empty.
Return value
0 if the table is empty, 1 if it contains any key-value pairs
top source mgcohashtable::cleanup
mgcohashtable::cleanup
Frees hash table resources, but the resources contained by the hash table.
top source mgcohashtable::init
result = mgcohashtable::init( [array_size=integral], key_type=0-15, value_type=0-15, key_example=key type, value_example=value type)
Create a hash table.
Return value
1 if successful; 0 otherwise
Keywords
- array_size in optional type=integral default=101
the size of the hash table; generally a prime is a good choice
- key_type in type=0-15
type code for keys; key_type or key_example must be present
- value_type in type=0-15
type code for values; value_type or key_example must be present
- key_example in type=key type
example of key type; key_type or key_example must be present
- value_example in type=value type
example of value type; value_type or value_example must be present
File attributes
| Modification date: | Mon Nov 29 18:32:28 2010 |
| Lines: | 865 |
| Docformat: | rst rst |
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