Chemistry::Elements - Perl extension for working with Chemical Elements
use Chemistry::Elements qw(get_name get_Z get_symbol);
# the constructor can use different input
$element = Chemistry::Elements->new( $atomic_number );
$element = Chemistry::Elements->new( $chemical_symbol );
$element = Chemistry::Elements->new( $element_name );
# you can make up your own attributes by specifying
# a method (which is really AUTOLOAD)
$element->molar_mass(22.989) #sets the attribute
$MM = $element->molar_mass #retrieves the value
There are two parts to the module: the object stuff and the exportable functions
for use outside of the object stuff. The exportable functions are discussed in
"Exportable functions".
Chemistry::Elements provides an easy, object-oriented way to keep track of your
chemical data. Using either the atomic number, chemical symbol, or element
name you can construct an Element object. Once you have an element object, you
can associate your data with the object by making up your own methods, which
the AUTOLOAD function handles. Since each chemist is likely to want to use his
or her own data, or data for some unforesee-able property, this module does
not try to be a repository for chemical data.
The Element object constructor tries to be as flexible as possible - pass it an
atomic number, chemical symbol, or element name and it tries to create the
object.
# the constructor can use different input
$element = Chemistry::Elements->new( $atomic_number );
$element = Chemistry::Elements->new( $chemical_symbol );
$element = Chemistry::Elements->new( $element_name );
Once you have the object, you can define your own methods simply by using them.
Giving the method an argument (others will be ignored) creates an attribute
with the method's name and the argument's value.
# you can make up your own attributes by specifying
# a method (which is really AUTOLOAD)
$element->molar_mass(22.989) #sets the attribute
$MM = $element->molar_mass #retrieves the value
The atomic number, chemical symbol, and element name can be retrieved in the
same way.
$atomic_number = $element->Z;
$name = $element->name;
$symbol = $element->symbol;
These methods can also be used to set values, although changing any of the three
affects the other two.
$element = Chemistry::Elements->new('Lead');
$atomic_number = $element->Z; # $atomic_number is 82
$element->Z(79);
$name = $element->name; # $name is 'Gold'
- new( Z | SYMBOL | NAME )
- Create a new instance from either the atomic number,
symbol, or element name.
- can( METHOD [, METHOD ... ] )
- Returns true if the package or object can respond to
METHOD. This distinguishes between class and instance methods.
- Z
- Return the atomic number of the element.
- name
- Return the name of the element.
- symbol
- Return the symbol of the element.
These functions can be exported. They are not exported by default. At the
moment, only the functional interface supports multi-language names.
- get_symbol( NAME|Z )
- This function attempts to return the symbol of the chemical
element given either the chemical symbol, element name, or atmoic number.
The function does its best to interpret inconsistent input data (e.g.
chemcial symbols of mixed and single case).
use Chemistry::Elements qw(get_symbol);
$name = get_symbol('Fe'); #$name is 'Fe'
$name = get_symbol('fe'); #$name is 'Fe'
$name = get_symbol(26); #$name is 'Fe'
$name = get_symbol('Iron'); #$name is 'Fe'
$name = get_symbol('iron'); #$name is 'Fe'
If no symbol can be found, nothing is returned.
Since this function will return the symbol if it is given a symbol, you can
use it to test whether a string is a chemical symbol (although you have to
play some tricks with case since get_symbol will try its best despite the
case of the input data).
if( lc($string) eq lc( get_symbol($string) ) )
{
#stuff
}
You can modify the symbols (e.g. you work for UCal ;) ) by changing the data
at the end of this module.
- get_name( SYMBOL|NAME|Z [, LANGUAGE] )
- This function attempts to return the name the chemical
element given either the chemical symbol, element name, or atomic number.
The function does its best to interpret inconsistent input data (e.g.
chemical symbols of mixed and single case).
$name = get_name('Fe'); #$name is 'Iron'
$name = get_name('fe'); #$name is 'Iron'
$name = get_name(26); #$name is 'Iron'
$name = get_name('Iron'); #$name is 'Iron'
$name = get_name('iron'); #$name is 'Iron'
If no Z can be found, nothing is returned.
Since this function will return the name if it is given a name, you can use
it to test whether a string is a chemical element name (although you have
to play some tricks with case since get_name will try its best despite the
case of the input data).
if( lc($string) eq lc( get_name($string) ) )
{
#stuff
}
You can modify the names (e.g. for different languages) by changing the data
at the end of this module.
- get_Z( SYMBOL|NAME|Z )
- This function attempts to return the atomic number of the
chemical element given either the chemical symbol, element name, or atomic
number. The function does its best to interpret inconsistent input data
(e.g. chemcial symbols of mixed and single case).
$name = get_Z('Fe'); #$name is 26
$name = get_Z('fe'); #$name is 26
$name = get_Z(26); #$name is 26
$name = get_Z('Iron'); #$name is 26
$name = get_Z('iron'); #$name is 26
If no Z can be found, nothing is returned.
Since this function will return the Z if it is given a Z, you can use it to
test whether a string is an atomic number. You might want to use the
string comparison in case the $string is not a number (in which case the
comparison will be false save for the case when $string is undefined).
if( $string eq get_Z($string) ) {
#stuff
}
The package constructor automatically finds the largest defined atomic number
(in case you add your own heavy elements).
You can pseudo-define additional methods to associate data with objects. For
instance, if you wanted to add a molar mass attribute, you simply pretend that
there is a molar_mass method:
$element->molar_mass($MM); #add molar mass datum in $MM to object
Similarly, you can retrieve previously set values by not specifying an argument
to your pretend method:
$datum = $element->molar_mass();
#or without the parentheses
$datum = $element->molar_mass;
If a value has not been associated with the pretend method and the object, the
pretend method returns nothing.
I had thought about providing basic data for the elements, but thought that
anyone using this module would probably have their own data. If there is an
interest in canned data, perhaps I can provide mine :)
XXX: Fill this stuff in later. For now see the test suite
I would like make this module easily localizable so that one could specify other
names or symbols for the elements (i.e. a different language or a different
perspective on the heavy elements). If anyone should make changes to the data,
i would like to get a copy so that i can include it in future releases :)
The source for this module is in Github:
https://github.com/briandfoy/chemistry-elements
brian d foy, "<
[email protected]>"
Copyright © 2000-2021, brian d foy <
[email protected]>. All rights
reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the Artistic License 2.0.