str = "x^2 + 12317         +X^2 -       Length"

str = "      x    ^  2  + y              ^   2   =   2   "

count = 8.4

print("count: #{count}   ")

if /^(\s*[a-zA-Z]+\s*\(\s*[0-9a-zA-Z]+\s*\)\s*[\+\-\*\/\=]\s*)?\s*[0-9a-zA-Z]+\s*\^?\s*[0-9a-zA-Z]*\s*[\+\-\*\/]\s*(\s*[0-9a-zA-Z]+\^?[0-9a-zA-Z]*\s*)\s*(\s*[\+\-\*\/\=]\s*[0-9a-zA-Z]+)?/ =~ str

  puts(MATCHED)

else

  puts(DISMATCHED)

end

 

str = str.gsub(/\s+/, "")

str = str.gsub(/\+/, " + ")

str = str.gsub(/\-/, " - ")

str = str.gsub(/\*/, " * ")

str = str.gsub(/\//, " \\ ")

str = str.gsub(/\=/, " = ")

puts(str)

 

运行结果

count: 8.4   matched

x^2 + y^2 = 2