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# Basic Operators

This section explains how to use basic operators in Python.

### Arithmetic Operators

Just as any other programming languages, the addition, subtraction, multiplication, and division operators can be used with numbers.

``` number = 1 + 2 * 3 / 4.0 print(number) ```

Try to predict what the answer will be. Does python follow order of operations?

Another operator available is the modulo (%) operator, which returns the integer remainder of the division. dividend % divisor = remainder.

``` remainder = 11 % 3 print(remainder) ```

Using two multiplication symbols makes a power relationship.

``` squared = 7 ** 2 cubed = 2 ** 3 print(squared) print(cubed) ```

Using Operators with Strings
Python supports concatenating strings using the addition operator:

``` helloworld = "hello" + " " + "world" print(helloworld) ```

Python also supports multiplying strings to form a string with a repeating sequence:

``` lotsofhellos = "hello" * 10 print(lotsofhellos) ```

Using Operators with Lists
Lists can be joined with the addition operators:

``` even_numbers = [2,4,6,8] odd_numbers = [1,3,5,7] all_numbers = odd_numbers + even_numbers print(all_numbers) ```

Just as in strings, Python supports forming new lists with a repeating sequence using the multiplication operator:
``` print([1,2,3] * 3) ```

## Exercise

The target of this exercise is to create two lists called `x_list` and `y_list`, which contain 10 instances of the variables `x` and `y`, respectively. You are also required to create a list called `big_list`, which contains the variables `x` and `y`, 10 times each, by concatenating the two lists you have created.

``` x = object() y = object()```

``` # TODO: change this code x_list = [x] y_list = [y] big_list = [] print("x_list contains %d objects" % len(x_list)) print("y_list contains %d objects" % len(y_list)) print("big_list contains %d objects" % len(big_list)) ```

```# testing code if x_list.count(x) == 10 and y_list.count(y) == 10: print("Almost there...") if big_list.count(x) == 10 and big_list.count(y) == 10: print("Great!") ```

Use the online editor below to try out all the codes and if you find any problem please comment below.