Computes the atomic mass of an equation

periodic_table.rb

table = {}
DATA.read.split(?\n).each do |line|
	ps = line.split(/\s+/)
	table[ps[2]] = ps[0].to_f
end
loop do
	i = gets.chomp
	input = i.scan(/([A-Z][a-z]?)([0-9]?)/)
	mass = 0
	input.each do |element|
		if element[1] == ""
			element[1] = 1
		end
		mass += table[element[0]] * element[1].to_f
	end
	puts "#{mass.round(1)} amu"
end

__END__
1.0079 	Hydrogen 	H 	1
4.0026 	Helium 	He 	2
6.941 	Lithium 	Li 	3
9.0122 	Beryllium 	Be 	4
10.811 	Boron 	B 	5
12.0107 	Carbon 	C 	6
14.0067 	Nitrogen 	N 	7
15.9994 	Oxygen 	O 	8
18.9984 	Fluorine 	F 	9
20.1797 	Neon 	Ne 	10
22.9897 	Sodium 	Na 	11
24.305 	Magnesium 	Mg 	12
26.9815 	Aluminum 	Al 	13
28.0855 	Silicon 	Si 	14
30.9738 	Phosphorus 	P 	15
32.065 	Sulfur 	S 	16
35.453 	Chlorine 	Cl 	17
39.0983 	Potassium 	K 	19
39.948 	Argon 	Ar 	18
40.078 	Calcium 	Ca 	20
44.9559 	Scandium 	Sc 	21
47.867 	Titanium 	Ti 	22
50.9415 	Vanadium 	V 	23
51.9961 	Chromium 	Cr 	24
54.938 	Manganese 	Mn 	25
55.845 	Iron 	Fe 	26
58.6934 	Nickel 	Ni 	28
58.9332 	Cobalt 	Co 	27
63.546 	Copper 	Cu 	29
65.39 	Zinc 	Zn 	30
69.723 	Gallium 	Ga 	31
72.64 	Germanium 	Ge 	32
74.9216 	Arsenic 	As 	33
78.96 	Selenium 	Se 	34
	79.904 	Bromine 	Br 	35
83.8 	Krypton 	Kr 	36
85.4678 	Rubidium 	Rb 	37
87.62 	Strontium 	Sr 	38
88.9059 	Yttrium 	Y 	39
91.224 	Zirconium 	Zr 	40
92.9064 	Niobium 	Nb 	41
95.94 	Molybdenum 	Mo 	42
98 	Technetium 	Tc 	43
101.07 	Ruthenium 	Ru 	44
102.9055 	Rhodium 	Rh 	45
106.42 	Palladium 	Pd 	46
107.8682 	Silver 	Ag 	47
112.411 	Cadmium 	Cd 	48
114.818 	Indium 	In 	49
118.71 	Tin 	Sn 	50
121.76 	Antimony 	Sb 	51
126.9045 	Iodine 	I 	53
127.6 	Tellurium 	Te 	52
131.293 	Xenon 	Xe 	54
132.9055 	Cesium 	Cs 	55
137.327 	Barium 	Ba 	56
138.9055 	Lanthanum 	La 	57
140.116 	Cerium 	Ce 	58
140.9077 	Praseodymium 	Pr 	59
144.24 	Neodymium 	Nd 	60
145 	Promethium 	Pm 	61
150.36 	Samarium 	Sm 	62
151.964 	Europium 	Eu 	63
157.25 	Gadolinium 	Gd 	64
158.9253 	Terbium 	Tb 	65
162.5 	Dysprosium 	Dy 	66
164.9303 	Holmium 	Ho 	67
167.259 	Erbium 	Er 	68
168.9342 	Thulium 	Tm 	69
173.04 	Ytterbium 	Yb 	70
174.967 	Lutetium 	Lu 	71
178.49 	Hafnium 	Hf 	72
180.9479 	Tantalum 	Ta 	73
183.84 	Tungsten 	W 	74
186.207 	Rhenium 	Re 	75
190.23 	Osmium 	Os 	76
192.217 	Iridium 	Ir 	77
195.078 	Platinum 	Pt 	78
196.9665 	Gold 	Au 	79
200.59 	Mercury 	Hg 	80
204.3833 	Thallium 	Tl 	81
207.2 	Lead 	Pb 	82
208.9804 	Bismuth 	Bi 	83
209 	Polonium 	Po 	84
210 	Astatine 	At 	85
222 	Radon 	Rn 	86
223 	Francium 	Fr 	87
226 	Radium 	Ra 	88
227 	Actinium 	Ac 	89
231.0359 	Protactinium 	Pa 	91
232.0381 	Thorium 	Th 	90
237 	Neptunium 	Np 	93
238.0289 	Uranium 	U 	92
243 	Americium 	Am 	95
244 	Plutonium 	Pu 	94
247 	Curium 	Cm 	96
247 	Berkelium 	Bk 	97
251 	Californium 	Cf 	98
252 	Einsteinium 	Es 	99
257 	Fermium 	Fm 	100
258 	Mendelevium 	Md 	101
259 	Nobelium 	No 	102
261 	Rutherfordium 	Rf 	104
262 	Lawrencium 	Lr 	103
262 	Dubnium 	Db 	105
264 	Bohrium 	Bh 	107
266 	Seaborgium 	Sg 	106
268 	Meitnerium 	Mt 	109
272 	Roentgenium 	Rg 	111
277 	Hassium 	Hs 	108