Assign values from string to attributes using patterns

I have strings like this (e.g.):

property1=[43.55;343.44]   -> String=[double;double]
property2>=45.3   ->String >= double

How can I get this values to attributes, when I define appriopriate patterns. I want to use this, inside other string e.g "any string propertie1=[43.55;343.44] any string properties2>=45.3 any string " and as result I want to assign values which match pattern to attributes:

String s=property1 
double a=43.55
double b=343.44

etc.