3. Precedence of Operators¶
We have now added a number of additional operators to those we learned in the previous chapters. It is important to understand how these operators relate to the others with respect to operator precedence. Python will always evaluate the arithmetic operators first (** is highest, then multiplication/division, then addition/subtraction). Next comes the relational (or comparison) operators. Finally, the logical operators are done last. This means that the expression x * 5 >= 10 and y - 6 <= 20 will be evaluated so as to first perform the arithmetic and then check the relationships. The and evaluation will be done last. Although many programmers might place parenthesis around the two relational expressions, it is not strictly necessary.
The following table summarizes the operator precedence from highest to lowest. A complete table for the entire language can be found in the Python Documentation.
| Level | Category | Operators |
|---|---|---|
| 7(high) | exponent | ** |
| 6 | multiplication | *,/,//,% |
| 5 | addition | +,- |
| 4 | relational | ==,!=,<=,>=,>,< |
| 3 | logical | not |
| 2 | logical | and |
| 1(low) | logical | or |
Check your understanding
-
Which of the following properly expresses the precedence of operators (using parentheses) in the following expression: 5*3 > 10 and 4+6==11
- ((5*3) > 10) and ((4+6) == 11)
- Yes, * and + have higher precedence, followed by > and ==, and then the keyword "and"
- (5*(3 > 10)) and (4 + (6 == 11))
- Arithmetic operators (*, +) have higher precedence than comparison operators (>, ==)
- ((((5*3) > 10) and 4)+6) == 11
- This grouping assumes Python simply evaluates from left to right, which is incorrect. It follows the precedence listed in the table in this section.
- ((5*3) > (10 and (4+6))) == 11
- This grouping assumes that "and" has a higher precedence than ==, which is not true.