OAU CSC 201 Practice Quiz

Variable x is incremented and printed twice.

l (or L) stands for long.

Case is always significant while dealing with identifiers in python.

he binary form of the number 29 is 11101. Hence the output of this expression is ‘0b11101’.

The code shown above demonstrates rebinding using a static method. This can be done with or without a decorator. The output of this code will be 100.

In Python, to define a block of code we use indentation. Indentation refers to whitespaces at the beginning of the line.

i takes values 0, 1, 2 and 3.

Infinity is a special case of floating point numbers. It can be obtained by float(‘inf’).

Python has a nifty feature called documentation strings, usually referred to by its shorter name docstrings. DocStrings are an important tool that you should make use of since it helps to document the program better and makes it easier to understand.

The string x is being shortened by one character in each iteration.

Built-in functions and user defined ones. The built-in functions are part of the Python language. Examples are: dir(), len() or abs(). The user defined functions are functions created with the def keyword.

When the value of x is equal to 8 (1000), then x>>2 (bitwise right shift) yields the value 0010, which is equal to 2. Hence the value of x is 8.

Padding is done towards the right-hand-side first when the final string is of even length.

Any odd number on being AND-ed with 1 always gives 1. Any even number on being AND-ed with this value always gives 0.

^ is the Binary XOR operator.

The elements of the tuple are accessed by their indices.

SyntaxError, True is a keyword and it’s value cannot be changed.

The order of precedence is: %, +. Hence the expression above, on simplification results in 4 + 3 = 7. Hence the result is 7.

The expression shown above rounds off the given number to the number of decimal places specified. Since the expression given specifies rounding off to two decimal places, the output of this expression will be 56.24. Had the value been x=56.234 (last digit being any number less than 5), the output would have been 56.23.

Variable names can be of any length.

All of the above examples show explicit conversion. However the expression int(’10.8’) results in an error.

Although the presence of parenthesis does affect the order of precedence, in the case shown above, it is not making a difference. The result of both of these expressions is 1.333333333. Hence the statement is true.

+ will append the element to the list.

In the code shown above, the value for a is substituted by l[0], that is ‘H’, the value of b is substituted by l[-1], that is ‘O’ and the value for c is substituted by l[1:3]. Here the use of *p is to unpack a tuple items into individual function arguments.

Loops over the values.

The @ symbol can be used as an alternate way to specify a function that needs to be decorated. The output of the codes shown above is the same. Hence they are equivalent. Therefore this statement is true.

The order of precedence is: **, //, +. The expression 4+2**5//10 is evaluated as 4+32//10, which is equal to 4+3 = 7. Hence the result of the expression shown above is 7.

Let us consider an example wherein a=2. The binary form of 2 is 0010. When we left shift this value by 2, we get 1000, the value of which is 8. Hence if we want to multiply a given number ‘a’ by 4, we can use the expression: a<<2.

range(0) is empty

Python shell throws a NoneType object back.

Id in this case will be the attribute of the instance.

he function sys.version can help us to find the version of python that we are currently working on. It also contains information on the build number and compiler used. For example, 3.5.2, 2.7.3 etc. this function also returns the current date, time, bits etc along with the version.

In python, power operator is x**y i.e. 2**3=8.

cmp(x, y) returns 1 if x > y, 0 if x == y and -1 if x < y.

Tuples are represented with round brackets.

Many languages have been implemented using both compilers and interpreters, including C, Pascal, and Python.

Error, objects of type int aren’t iterable.

The code shown above returns a new list containing only those elements of the list l which do not amount to zero. Hence the output is: [1, 2, ‘hello’].

The one’s complement of a value is obtained by simply changing all the 1’s to 0’s and all the 0’s to 1’s. Hence the one’s complement of 110010101 is 001101010.

In the code shown above, @sf is not a decorator but only a decorator line. The ‘@’ symbol represents the application of a decorator. The decorator here is the function mk.

The code shown above is used to swap the contents of two memory locations using bitwise X0R operator. Hence the output of the code shown above is: 20 10.

The code shown above shows the formatting option on the same value, that is 4.56, where in the second case, the value is enclosed in a list. Hence the output of the code shown above is:
‘4.56’, ‘[4.56]’

For order of precedence, just remember this PEMDAS (similar to BODMAS).

The expression not(10<20) returns false. The expression not(10>30) returns true. The and operation between false and true returns false. Hence the output is false.

The code shown above converts the given arguments to hexadecimal and decimal values and prints the result. This is done using the format specifiers %x and %d respectively. Hence the output of the code shown above is: ‘ff, 255’.

The code shown above rounds the floating point value to two decimal places. In this code, a variety of addition formatting features such as zero padding, total field width etc. Hence the output of this code is: ‘3.35 | 03.35 | +003.3’.