#8 Python Playground: Type Conversion | Computer Programming & Coding for Kids & Beginners

Magic8

8-0

Liam
Type Conversion in Python

8-1

Liam
Hi, Emma!

Emma
Hi, Liam!

Liam
Do you remember the data types?

Emma
Sure!
There are strings, integers, floating point and so on in data types.

Figure

Liam
That’s right!
What happens when you add the string "Hello" and the number 100?

Figure

Emma
Do you mean adding strings and numbers?
I can't calculate it in Python because the data types are different.

Liam
That’s right!
We can't add up strings and numbers.
So, can you add the number 15 to the string 100?

Emma
Because of the different data types, I can't actually add strings and numbers together.
How can I calculate it?

Liam
You can calculate it by converting the character string 100 to the number 100.

Emma
How do I change the data type?

8-2

Liam
Data Type Conversion in Python

Liam
When you want to convert the data, use the command to convert the data.

Emma
That's useful.
What types of commands are available to convert data?

Liam
int function converts string to integer.
float function converts string to floating point number.
str function converts integer and floating point number to string.

Emma
We can use these commands to convert the data.

Liam
Exactly!
First, let’s try adding the string "100" to the integer 15.
Create a new file in IDLE and write the code like this.
Save and then run it.
Then an error is displayed.

Emma
It is not possible to calculate with string and integer.
We need to convert the string to the integer before we can calculate it.

Liam
That’s right!
So, we use int function to convert the string to an integer and then calculate it.
Create a new file in IDLE and write the code like this.
Save and then run it.

a="100"
print(int(a)+15)

Output
115

Emma
Now we've done the math.
We were able to calculate it by converting the string type 100 to a number 100.

Liam
Exactly!

8-3

Liam
How to check if it can be converted

Emma
Can we check if we can convert in advance to avoid errors?

Liam
We can prevent such errors by checking in advance when they are likely to occur.
We can use the isdigit function to check if the variable can be converted to a number correctly.

Figure

Liam
True is displayed when conversion is possible, and False is displayed when conversion is not possible.

Emma
If we check beforehand and convert only when True is displayed, there will be no error.

Liam
That’s right!
Let's try it out and see if we can convert the strings "100" and “Hello!"
Create a new file in IDLE and write the code like this.
Save and then run it.

a="100"
b="Hello!"

Output
True
False

Emma
It turns out that the string 100 can be converted to an integer and the string Hello! cannot be converted.

Liam
That’s right.

8-0

Emma
In this lesson, we learned about data type conversions.

Liam
Well done!