OAU CSC 201 Practice Quiz

Execute in the shell.

The code shown above shows a general decorator which can work with any number of arguments.

‘.py’ is the correct extension of the Python file. Python programs can be written in any text editor. To save these programs we need to save in files with file extension ‘.py’.

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’.

The result of the expression shown above is (6.0, 16.0). This is because the result is automatically rounded off to one decimal place.

Variable x is incremented and printed twice.

In the code shown above, the function mk() is the decorator. The function which is getting decorated is mk2(). The return function is given the name p().

The line of code can be translated to state that ‘f’ is printed if the argument passed to the Boolean function amount to zero. Else ‘t’ is printed. The argument given to the Boolean function in the above case is ‘spam’, which does not amount to zero. Hence the output is t.

You can’t perform mathematical operation on string even if the string is in the form: ‘1234…’.

Loops over the values.

The loop is entered twice.

The line of code shown above can be simplified to state that ‘hello’ should be printed if the argument passed to the Boolean function amounts to zero, else ‘morning’ will be printed.

Python language is designed by a Dutch programmer Guido van Rossum in the Netherlands.

The function seed is a function which is present in the random module. The functions sqrt and factorial are a part of the math module. The print function is a built-in function which prints a value directly to the system output.

The formatting option print(“%Ns”,X) helps us add ‘N’ number of spaces before a given string ‘X’. Hence the output for the code snippet shown above will be 56 blank spaces before the string “san-foundry”.

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

Execute help(round) in the shell to get details of the parameters that are passed into the round function.

Carefully look at the colons.

[::-1] reverses the string.

i takes values 0, 1, 2 and 3.

Error, objects of type int aren’t iterable.

Cause a decimal value of 0 to appear as output.

In the code shown above, we have used a decorator in order to avoid the Zero Division Error. Hence the output of this code is:

    hello
    NO

The expression shown above is evaluated as: 2+9*(36-8)/10, which simplifies to give 2+9*(2.8), which is equal to 2+25.2 = 27.2. Hence the result of this expression is 27.2.

The expressions are evaluated as: 4%3 and 6//2 respectively. This results in the answer (1,3). This is because the associativity of both of the expressions shown above is left to right.

Addition and Subtraction” are at the same precedence level. Similarly, “Multiplication and Division” are at the same precedence level. However, Multiplication and Division operators are at a higher precedence level than Addition and Subtraction operators.

in is a keyword.

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.

Class is a user defined data type.

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.

The instance of the string returned by upper() is being printed.

// is integer operation in python 3.0 and int(..) is a type cast operator.

The Boolean function returns true if the argument passed to the bool function does not amount to zero. In the first example, the string ‘False’ is passed to the function bool. This does not amount to zero and hence the output is true. In the second function, an empty list is passed to the function bool. Hence the output is false.

The symbol ‘&’ represents bitwise AND. This gives 1 if both the bits are equal to 1, else it gives 0. The binary form of 15 is 1111 and that of 12 is 1100. Hence on performing the bitwise AND operation, we get 1100, which is equal to 12.

Bitwise XOR gives 1 if either of the bits is 1 and 0 when both of the bits are 1.

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

The binary form of -44 is 00101100. The one’s complement of this value is 11010011. On adding one to this we get: 11010100 (two’s complement).

The binary value of 0x35 is 110101 and that of 0x75 is 1110101. On OR-ing these two values we get the output as: 1110101, which is equal to 117. Hence the result of the above expression is 117.

The binary form of 1 is 0001. The expression x<<2 implies we are performing bitwise left shift on x. This shift yields the value: 0100, which is the binary form of the number 4.

Loops over the keys of the dictionary.

The above expression is an example of explicit conversion. It is evaluated as: float(4+int(2.39)%2) = float(4+2%2) = float(4+0) = 4.0. Hence the result of this expression is 4.0.

The code shown above shows a general decorator which can work with any number of arguments.

SyntaxError, there shouldn’t be a space between + and = in +=.SyntaxError, there shouldn’t be a space between + and = in +=.

The highest precedence is that of the exponentiation operator, that is of **.

The code shown above results in an error. This is because we have switched from automatic field numbering to manual field numbering, that is, from {} to {1}. Hence this code results in an error.

Each object in Python has a unique id. The id() function returns the object’s id.

Objects of type int have no attribute upper().

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

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