2.1.2.6 Python literals

Ints vs. floats

The decimal point is essentially important in recognizing floating-point numbers in Python.

Look at these two numbers:

4 4.0

You may think that they are exactly the same, but Python sees them in a completely different way.

4 is an integer number, whereas 4.0 is a floating-point number.

The point is what makes a float.

On the other hand, it's not only points that make a float. You can also use the letter e.

When you want to use any numbers that are very large or very small, you can use scientific notation.

Take, for example, the speed of light, expressed in meters per second. Written directly it would look like this: 300000000.

To avoid writing out so many zeros, physics textbooks use an abbreviated form, which you have probably already seen: 3 x 108.

It reads: three times ten to the power of eight.

In Python, the same effect is achieved in a slightly different way - take a look:

3E8

The letter E (you can also use the lower-case letter e - it comes from the word exponent) is a concise record of the phrase times ten to the power of.

Note:

• the exponent (the value after the E) has to be an integer;
• the base (the value in front of the E) may be an integer.