Summary Test 2 Answers - SAYA HACKER

  1. Knowing that a function named f() resides in a module named m, and was imported using the following statement


       from mod import fun

    choose the right way to invoke it:

    • fun()
    • mod.fun()
    • mod::fun()
    • mod:fun()
  2. What output will appear after running the following snippet?


       import math
       print(dir(math))
    • an error message
    • a string containing the fully qualified name of the module
    • a list of all the entities residing in the math module
    • the number of all the entities residing in the math module
  3. The compiled Python bytecode is stored in files having names ending with:

    • py
    • pyb
    • pc
    • pyc
  4. Assuming that all three files, a.py, b.py, and c.py reside in the same folder, what will be the output produced by running the c.py file?


       # file a.py
       print(“a”,end=”)

       #file b.py
       import a
       print(“b”,end=”)

       #file c.py
       print(“c”,end=”)
       import a
       import b
    • cba
    • abc
    • bac
    • cab
  5. What will be the output of the following code, located in file p.py?


       print(__name__)
    • p.py
    • main
    • __p.py__
    • __main__
  6. The following statement


       from a.b import c

    causes the import of:

    • entity a from module b from package c
    • entity b from module a from package c
    • entity c from module b from package a
    • entity c from module a from package b
  7. If there are more than one except: branches after the try:, we can say that:

    • one or more of the try: blocks will be executed
    • none of the try: blocks will be executed
    • not more than one try: block will be executed
    • exactly one of the try: blocks will be executed
  8. What will be the output of the following snippet?   try:      raise Exception
       except BaseException:
          print(“a”)
       except Exception:
          print(“b”)
       except:
          print(“c”)
    • c
    • b
    • it will cause an error
    • a
  9. The following line of code:


        for line in open(‘text.txt’,’rt’):
    • is valid as open returns an iterable object
    • is invalid as open returns a non-iterable object
    • is invalid as open returns nothing
    • may be valid if line is a list
  10. What will be the output of the following snippet?

       try:
          raise Exception
       except:
          print(“c”)
       except BaseException:
          print(“a”)
       except Exception:
          print(“b”)
    • a
    • c
    • b
    • it will cause an error
  11. The following statement:


    assert var != 0
    • will stop the program when var == 0
    • is erroneous
    • has no effect
    • will stop the program when var != 0
  12. The following code prints:


       x = “\\\\”
       print(len(x))
    • 2
    • 1
    • 3
    • the code will cause an error
  13. The following code prints:


       x = “\\\”
       print(len(x))
    • 3
    • the code will cause an error
    • 1
    • 2
  14. The following code prints:

       print(chr(ord(‘p’) + 2))
    • s
    • t
    • q
    • r
  15. The following code:

        print(float(“1.3”))
    • raises a ValueError exception
    • prints 13
    • prints 1,3
    • 1.3
  16. If the class’s constructor is declared as below, which one of the assignments is invalid?

        class Class:
           def __init__(self,val=0):
               pass
    • object = Class(None)
    • object = Class(1)
    • object = Class()
    • object = Class(1,2)
  17. What will be output of the following code?

       class A:
          def __init__(self,v = 2):
             self.v = v
          def set(self,v = 1):
             self.v += v
              return self.v
       a = A()
       b = a
       b.set()
       print(a.v)
    • 0
    • 3
    • 1
    • 2
  18. What will be output of the following code?

        class A:
            A = 1
            def __init__(self):
               self.a = 0
        print(hasattr(A,’a’))
    • 1
    • False
    • 0
    • True
  19. What will be the result of executing the following code?

       class A:
          pass
       class B(A):
          pass
       class C(B):
          pass
       print(issubclass(A,C))
    • it will print False
    • it will print True
    • it will print 1
    • it will raise an exception
  20. The sys.stderr stream is normally associated with:

    • the keyboard
    • a null device
    • the screen
    • the printer
  21. What will be the effect of running the following code?

       class A:
          def __init__(self,v):
              self.__a = v + 1
       a = A(0)
       print(a.__a)
    • it will print 1
    • it will print 2
    • it will raise an AttributeError exception
    • it will print 0
  22. What will be the result of executing the following code?

       class A:
          def __init__(self):
             pass
       a = A(1)
       print(hasattr(a,’A’))
    • it will print True
    • it will raise an exception
    • it will print False
    • it will print 1
  23. What will be the result of executing the following code?

       class A:
          def a(self):
             print(‘a’)
       class B:
          def a(self):
             print(‘b’)
       class C(B,A):
          def c(self):
             self.a()
       o = C()
       o.c()
    • it will print c
    • it will raise an exception
    • it will print b
    • it will print a
  24. What will be the result of executing the following code?

       try:
          raise Exception(1,2,3)
       except Exception as e:
          print(len(e.args))
    • it will print 2
    • it will print 1
    • it will raise an unhandled exception
    • it will print 3
  25. What will be the result of executing the following code?

       def I(n):
          s = ‘+’
          for i in range(n):
             s += s
             yield s
       for x in I(2):
          print(x,end=”)
    • it will print ++
    • it will print ++++++
    • it will print +
    • it will print +++
  26. What will be the result of executing the following code?

       class I:
          def __init__(self):
             self.s = ‘abc’
             self.i = 0
          def __iter__(self):
             return self
          def __next__(self):
             if self.i == len(self.s):
                raise StopIteration
             v = self.s[self.i]
             self.i += 1
             return v
       for x in I():
          print(x,end=”)
    • 012
    • abc
    • cba
    • 210
  27. What will be the result of executing the following code?

       def o(p):
          def q():
             return ‘*’ * p
          return q
       r = o(1)
       s = o(2)
       print(r() + s())

    • it will print ****
    • it will print **
    • it will print ***
    • it will print *
  28. If s is a stream opened in read mode, the following line will:

       q = s.read(1)
    • read 1 character from the stream
    • read 1 kilobyte from the stream
    • read 1 line from the stream
    • read 1 buffer from the stream
  29. Assuming that the open() invocation has gone successfully, the following snippet will:

       for x in open(‘file’,’rt’):
          print(x)
    • read the file character by character
    • cause an exception
    • read the whole file at once
    • read the file line by line
  30. If you want to fill a byte array with data read in from a stream, you’d use:

    • the readinto() method
    • the read() method
    • the readbytes() method
    • the readfrom() method

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