Chapter 7

#Exercise 7.1 Write a program to read through a file and print the contents of the file (line by line) all in upper case.
user_input=input('Enter a File name:')
try:
    fin=open(user_input)
    for line in fin:
        print(str.upper(line),end='')
    fin.close()
except:
    print('File doesn\'t exist')

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#Exercise 7.2 Write a program to prompt for a file name, and then read through the file and look for lines of the form:
def spamcount(a,b):
    for line in a:
        l=line.split()
        if l==[]:continue
        if 'X-DSPAM-Confidence:'not in l[0]:continue
        b.append(l[1])
    return b

ui=input('Enter a File name:')
lis=[]
j=0
try:
    fin=open(ui)
    spamcount(fin,lis)
    for i in lis:
        j=float(i)+j
    print('Average Spam Confidence: ',format(j/len(lis),'.12g'))
    fin.close()
except:
    print('Oops......file doesn\'t exist')

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#Exercise 7.3 Sometimes when programmers get bored or want to have a bit of fun, they add a harmless Easter Egg to their program (en.wikipedia.org/wiki/Easter_egg_(media)). Modify the program that prompts the user for the file name so that it prints a funny message when the user types in the exact file name ’na na boo boo’. The program should behave normally for all other files which exist and don’t exist.
user=input("Enter a File name:")
try:
    count=0
    fin=open(user)
    for line in fin:
        if line.startswith('Subject'):
            count+=1
    fin.close()
    print('There were %d subject lines in '% count+'%s' % user)
except:
    if user=='na na boo boo':
        print("NA NA BOO BOO TO YOU - You have been punk'd!")
    else:
        print("File cannot be opened: ",user)