# Precedence Order In Python

Python is a popular programming language known for its simple syntax and ease of use. The precedence order, which specifies the order in which operators are evaluated in an expression, is one of Python's important features.Understanding the precedence order is important for writing correct Python code, as it can affect the results of an expression.

The precedence order is a set of rules that dictate how expressions are evaluated in Python. When an expression contains multiple operators, the evaluation of the first operator depends on the precedence order. This is important because different operators have different levels of precedence, and evaluating them in the wrong order can lead to incorrect results.

Python follows the standard mathematical rules of precedence, which are:

1. Parentheses
2. Exponents
3. Multiplication and Division

These rules mean that expressions within parentheses are evaluated first, followed by exponents, then multiplication and division, and finally addition and subtraction. Let's take a closer look at each of these degrees of precedence.

### Parentheses

Expressions within parentheses are evaluated first, regardless of the other operators in the expression. This indicates that the parentheses' contents are evaluated first when an expression contains them.

For example, consider the following expression:

``````result = (2 + 3) * 4
print(result)``````

Output:

`20`

In this expression, the parentheses around 2 + 3 indicate that this sub-expression should be evaluated first. So, the expression inside the parentheses is evaluated first, giving a result of 5. Then, the multiplication operator is evaluated, giving a final result of 20.

Moreover, parentheses can be layered inside of other parentheses, allowing for more complex expressions.

Example:

``````result = ((2 + 3) * 4) / (5 - 1)
print(result)``````

Output:

`5.0`

In this expression, the parentheses around 2 + 3 are evaluated first, giving a result of 5. Then, the multiplication operator is evaluated, giving a result of 20. Next, the parentheses around 5 - 1 are evaluated, giving a result of 4. Finally, the division operator is evaluated, giving a final result of 5.

Exponents

Exponents are evaluated next, before multiplication and division, and before addition and subtraction. Exponents are indicated using the ** operator.

For example, consider the following expression:

``````result = 2 ** 3 * 4
print(result)``````

Output:

`32`

In this expression, the exponent operator ** is evaluated first, giving a result of 8. Then, the multiplication operator is evaluated, giving a final result of 32.

Exponents can also be combined with parentheses to create more complex expressions.

Example:

``````result = (2 + 3) ** 2
print(result)``````

Output:

`25`

In this expression, the parentheses indicate that 2 + 3 should be evaluated first, giving a result of 5. Then, the exponent operator ** is evaluated, giving a final result of 25.

### Multiplication and Division

As division and multiplication have the same amount of precedence, their results are compared left to right. This means that the multiplication and division operators are evaluated in the order in which they appear in an expression if it contains both of them.

For example, consider the following expression:

``````result = 10 / 2 * 3
print(result)``````

Output:

`15.0`

In this expression, the division operator / is evaluated first, giving a result of 5. Then, the multiplication operator * is evaluated, giving a final result of 15.

It's important to note that division in Python 2.x behaves differently than in Python 3.x. In Python 2.x, the division between two integers results in an integer, which means any remainder is truncated. Toavoid this behavior, you can use the float() function to convert one or both of the integers to a float before performing the division. In Python 3.x, the division between two integers results in a float, which means that any remainder is preserved.

Moreover, addition and subtraction are evaluated from left to right with the same amount of precedence.This indicates that the addition and subtraction operators are evaluated in the order in which they appear in the expression if an expression contains both types of operators.

For example, consider the following expression:

``````result = 10 - 5 + 3
print(result)``````

Output:

`8`

In this expression, the subtraction operator - is evaluated first, giving a result of 5. Then, the addition operator + is evaluated, giving a final result of 8.

It is important to note that the order of evaluation can affect the result of an expression.

Example:

``````result = 2 + 3 * 4
print(result)``````

Output:

`14`

The multiplication operator * is evaluated first in this equation because it has higher precedence than the addition operator +.This gives a result of 12. Then, the addition operator + is evaluated, giving a final result of 14.

If we want to change the order of evaluation, we can use parentheses to force a specific order.

Example:

``````result = (2 + 3) * 4
print(result)
``````

Output:

`20`

In this expression, the parentheses indicate that 2 + 3 should be evaluated first, giving a result of 5. Then, the multiplication operator * is evaluated, giving a final result of 20.

### Operator Precedence Table

To summarize the precedence order in Python, we can create a table that shows the order in which operators are evaluated, from highest to lowest precedence:

The order in which Python's operators are evaluated is shown in the table below. The operators at the top of the table are given priority over the operators at the bottom.For example, parentheses have the highest precedence, followed by exponents, multiplication and division, and so on.

### Overriding Precedence with Parentheses

As previously noted, parenthesis can be used to impose a certain order of evaluation and override the default precedence order.This is particularly useful when writing complex expressions that contain multiple operators.

For example, consider the following expression:

Example:

``````result = 2 + 3 * 4
print(result)``````

Output:

`14`

As we saw earlier, this expression is evaluated as 2 + (3 * 4), which gives a result of 14. However, if we want to change the order of evaluation, we can use parentheses to force a specific order:

Example:

``````result = (2 + 3) * 4
print(result)``````

Output:

`20`

In this expression, the parentheses force 2 + 3 to be evaluated first, giving a result of 5. Then, the multiplication operator * is evaluated, giving a final result of 20.

It is important to note that while parentheses can be used to override the default precedence order, overusing them can make code difficult to read and understand. It's important to use parentheses judiciously and to follow best practices for writing clear and concise code.

### Conclusion

The precedence order is an important concept in Python, as it determines the order in which operators are evaluated.