Python: Input-Output (Solutions)

Raw input

  1. Solution:

    food = raw_input("What is your favourite food? ")
    
    print "I also like", food
    
  2. Solution:

    a_and_b = raw_input("Write two integers: ")
    words = a_and_b.split()
    a = int(words[0])
    b = int(words[1])
    
    answer = raw_input("how much is " + str(a) + " " + str(b) " ? ")
    result = int(answer)
    
    print a + b == answer
    
  3. Solution:

    key = raw_input("give me a key: ")
    value = raw_input("give me a value: ")
    
    dictionary = {key: value}
    # or
    dictionary = {}
    dictionary[key] = value
    
    print "dictionary =", dictionary
    
  4. Solution:

    name = raw_input("Give me your full name: ")
    
    fixed_words = [word[0].upper() + word[1:].lower()
                         for word in name.split()]
    print "Your name is:", " ".join(fixed_words)
    

Filesystem

  1. Solution:

    f = open("data/aatable", "r")
    # or
    f = open("data/aatable")
    
    rows = f.readlines()
    print type(rows)                           # list
    print type(rows[0])                        # str
    print len(rows)
    
    f.close()
    
  2. Solution:

    f = open("data/aatable")
    
    first_row = f.readline()
    print "The first row is: ", first_row
    
    remaining_rows = f.readlines()
    print "another", len(remaining_rows), " rows are left"
    
    remaining_rows_bis = f.readlines()
    print "then, another", len(remaining_rows_bis), "rows are left"
    
    # In the last case, 0 rows should be left: the first
    # readlines() already read all the lines of f
    
    f.close()
    
  3. Solution:

    f = open("output.txt", "w")
    f.write("check one two three check")
    f.close()
    
    g = open("output.txt", "r")
    print g.readlines()
    g.close()
    
  4. Solution:

    verses = [
        "S'i fosse fuoco, arderei 'l mondo"
        "s'i fosse vento, lo tempestarei"
    ]
    
    f = open("poetry.txt", "w")
    f.write("\n".join(verses))
    f.close()
    

    Now let’s try with "a":

    f2 = open("poetry2.txt", "a")
    f2.write(verses[0] + "\n")
    f2.close()
    
    f2 = open("poetry2.txt", "a")
    f2.write(verses[1] + "\n")
    f2.close()
    

    And if we use "w" on "poetry2.txtx":

    f = open("poetry2.txt", "w")
    # Here we do absolutely nothing to f, we just close it
    f.close()
    

    we can see that now "poetry2.txt" is empty! This happens as a consequence of using "w" instead of "a".

  5. Let’s write in the file trick.py:

    myself = open("trick.py")
    print myself.read()
    myself.close()
    

    Let’s execute the file to verify that it’s working as we want: from a shell, let’s write:

    python trick.py