"""
Exercise 4.4 from "A primer on...".
Read several temperature values from a
file containing both text and numbers. 
Solution method:
- Skip the first three lines
- Process the rest with a for loop, using 
split() to extract the last item on each line. 
"""

#empty list to be filled with values:
Fvals = []

with open('Fdeg.txt', 'r') as infile:
    for i in range(3):
        infile.readline()   

    for line in infile:    
        words = line.split()
        F = words[-1]
        Fvals.append(float(F))

#now compute the C values and store in a list:
Cvals = []
for F in Fvals:
    C = (F - 32) * 5 / 9
    Cvals.append(C)


#traverse both lists and write numbers to file:
with open('FCdeg.txt','w') as outfile:
    for F, C in zip(Fvals, Cvals):
        outfile.write(f'{F:6.2f} {C:6.2f} \n')

"""
Terminal> python f2c_file_read_write.py 
(no output to the screen, only a new file)
"""