Python variables, expressions, and data types

Front

What will this code output?
print("confusion")

Back

confusion

Front

In the following code, what is happening?
foo = "bar"

Back

A variable named foo is being created, with a value of "bar"

Front

If foo is equal to 3 and x is equal to 4, what is the value of foo after this operation? foo = foo + x

Back

7

Answer explanation

When a variable is on the left side of the assignment operator (=) it is the place where the result is stored. When it is on the right side, it's value is used as part of the operation. Since foo is 3 and x is 4:

foo = foo + x

foo = 3 + 4

foo = 7

We say that 7 "overwrites" the old value of foo.

Front

In the following code, what value will be assigned to the variable "cat"?
mouse, cat, dog = "small", "medium", "large"

Back

medium

Answer explanation

As explained in the W3 Schools tutorial, when you have a list of variables and a list of values, the values are assigned in order to the variables.

Note that a list of values is NOT the same as a string of values!

foo, bar, bam = "one", "two", "three" <- this is a list of values

foo, bar, bam = "one, two, three" <- this is a string containing commas which look like a list

The second line will generate an error, as there are three variables, but only one text string.

Front

What will the following code output?
biff = 3.4
print(biff)

Back

3.4

Answer explanation

The print() function will print any type of variable.

Front

What is type casting?

Back

It allows a piece of data to have it's data type changed, e.g. an integer could be changed to a string.

Front

Which of the following input commands would allow the user to receive and store a string from the keyboard? Options: string = input("Please enter a string:") , string = int(input("Please enter a string:")) , string = float(input("Please enter a string:")) , string = bool(input("Please enter a string:"))

Back

string = input("Please enter a string:")

Front

What is the minimum number of variables needed to calculate the average age of 5 pupils in a class?

Back

2

Answer explanation

Since we know there are 5 students, we only need one variable to get the pupil's age each time and one variable to keep track of the running total. We can then divide the total by 5 to get the average.

If we did not know the number of students, we would need an additional variable to keep track of that.

Front

Which symbol represents multiplication?

Back

*

Front

Which symbol is used for exponents?

Back

**