Write code elegantly: use Python operator precedence order flexibly

Flexibly apply Python operator priority order and write more elegant code

Python is a powerful programming language with rich operators and expressions . When writing Python code, correct use of operator precedence order can make the code more concise and readable. This article will introduce how to flexibly apply the precedence order of Python operators and provide specific code examples.

1. Priority of arithmetic operators

In Python, the priorities of arithmetic operators from high to low are: multiplication, division, remainder, addition and Subtraction. In expressions that use multiple arithmetic operators, parentheses can be used to explicitly specify the order of operations. Here is a sample code:

result = 2 + 3 * 4 / 2 - 1
print(result)  # 输出结果为 9.0

In this example, multiplication and division have higher priority than addition and subtraction, so first calculate 3 * 4 to get 12, then calculate 12 / 2 to get 6, and finally add Adding 2 and subtracting 1 gives us a result of 9.0.

2. Priority of comparison operators

Comparison operators are used to compare the values ​​of two expressions, and their precedence is lower than arithmetic operators. Common comparison operators are equal to (==), not equal to (!=), greater than (>), less than (=), and less than or equal to (

x = 5
y = 10
z = 5

print(x == y)  # 输出结果为 False
print(x != y)  # 输出结果为 True
print(x < y)   # 输出结果为 True
print(x >= z)  # 输出结果为 True

In this example, comparison operators are used to determine the relationship between x and y, and the results are printed. As you can see, comparison operators have a lower priority, so they can be written directly in the code in a natural order.

3. Priority of logical operators

Logical operators are used to join multiple expressions together and return a Boolean value. Common logical operators include logical AND (and), logical OR (or) and logical negation (not). They have lower precedence than comparison operators. The following is a sample code:

x = 5
y = 10
z = 5

print(x == z and y > z)  # 输出结果为 True
print(x == y or y == z)  # 输出结果为 False
print(not(x == y))       # 输出结果为 True

In this example, logical operators are used to determine whether multiple expressions are true or false, and the results are printed. As you can see, logical operators have a lower priority, so they can be written directly in the code in a natural order.

4. Priority of assignment operator

The assignment operator is used to assign a value to a variable. In Python, assignment operators have lower precedence, so in case of consecutive assignments, assignments are made from right to left. Here is a sample code:

x = 5
y = 10
z = 10

x = y = z

print(x)  # 输出结果为 10
print(y)  # 输出结果为 10
print(z)  # 输出结果为 10

In this example, first assign the value of z to y, and then assign the value of y to x. Eventually, the values ​​of x, y, and z all become 10.

Summary:

Flexible application of the priority order of Python operators can make the code more concise and readable. Errors caused by operator precedence can be avoided by correctly using parentheses to explicitly specify the order of operations. When writing code, writing operators and expressions in a natural order can make the code more intuitive and easier to understand. Finally, using more parentheses to clarify the priority of operations can make the code more readable and robust.

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