I have data that are long. I would like to generate a new variable that takes on the value of a separate variable is.

This is what my data look like:
classroomid score subject
13425 5.166667 3 = science
13425 5.055555 1 = language
13425 5.472222 2 = math
13425 5.777778 6 = other
This is what I would like my data to look like. Essentially, if the subject is language, I want to “newscore” to take on the value of science’s score. I want all other subjects to have the same score otherwise.
classroomid score subject newscore
13425 5.166667 3 = science 5.166667
13425 5.055555 1 = language 5.166667
13425 5.472222 2 = math 5.472222
13425 5.777778 6 = other 5.777778