Question

I’m doing some web scraping, this is the format for the data

Sr.No.  Course_Code Course_Name Credit  Grade   Attendance_Grade

The actual string that i receive is of the following form

1 CA727 PRINCIPLES OF COMPILER DESIGN 3 A M

The things that I am interested in are the Course_Code, Course_Name and the Grade, in this example the values would be

Course_Code : CA727
Course_Name : PRINCIPLES OF COMPILER DESIGN
Grade : A

Is there some way for me to use a regular expression or some other technique to easily extract this information instead of manually parsing through the string.
I’m using jruby in 1.9 mode.

Answer 1

Let’s use Ruby’s named captures and a self-describing regex!

course_line = /
    ^                  # Starting at the front of the string
    (?<SrNo>\d+)       # Capture one or more digits; call the result "SrNo"
    \s+                # Eat some whitespace
    (?<Code>\S+)       # Capture all the non-whitespace you can; call it "Code"
    \s+                # Eat some whitespace
    (?<Name>.+\S)      # Capture as much as you can
                       # (while letting the rest of the regex still work)
                       # Make sure you end with a non-whitespace character.
                       # Call this "Name"
    \s+                # Eat some whitespace
    (?<Credit>\S+)     # Capture all the non-whitespace you can; call it "Credit"
    \s+                # Eat some whitespace
    (?<Grade>\S+)      # Capture all the non-whitespace you can; call it "Grade"
    \s+                # Eat some whitespace
    (?<Attendance>\S+) # Capture all the non-whitespace; call it "Attendance"
    $                  # Make sure that we're at the end of the line now
/x

str = "1   CA727   PRINCIPLES OF COMPILER DESIGN   3   A   M"
parts = str.match(course_line)

puts "
Course Code: #{parts['Code']}
Course Name: #{parts['Name']}
      Grade: #{parts['Grade']}".strip

#=> Course Code: CA727
#=> Course Name: PRINCIPLES OF COMPILER DESIGN
#=>       Grade: A