List Manipulation Without NumPy

withoutNumPy.py

import pylab

def loadfile():
    inFile = open('julyTemps.txt', 'r')
    high =[]; low = []
    for line in inFile:
        fields = line.split()
        if len(fields) < 3 or not fields[0].isdigit():
            pass
        else:
            high.append(int(fields[1]))
            low.append(int(fields[2]))
    return low, high
    
def producePlot(lowTemps, highTemps):
    diffTemps = [highTemps[i] - lowTemps[i] for i in range(len(lowTemps))]
    pylab.title('Day by Day Ranges in Temperature in Boston in July 2012')
    pylab.xlabel('Days')
    pylab.ylabel('Temperature Ranges')
    return pylab.plot(range(1,32),diffTemps)
    
producePlot(loadfile()[1], loadfile()[0])