Python Logical OR Operator Usage Explained

a = ‘python’
print(‘hello,’, a or ‘world’)
b = ”
print(‘hello,’, b or ‘world’)

Introduction

Okay, let’s see. I need to figure out what this Python code does. The user has two print statements with some variables, and they’re using the ‘or’ operator. Hmm.

First, looking at the first part: a = ‘python’. Then print(‘hello,’, a or ‘world’). So, the ‘or’ operator here is checking if ‘a’ is truthy. Since ‘a’ is a non-empty string, it’s truthy, right? So a or ‘world’ should evaluate to ‘python’, so the first print would be ‘hello, python’.

Then, b = ”. So that’s an empty string. Then print(‘hello,’, b or ‘world’). Now, since b is an empty string, which is falsy in Python, the ‘or’ operator will return the second value, which is ‘world’. So the second print would be ‘hello, world’.

Wait, let me double-check. The ‘or’ operator returns the first operand if it’s truthy, otherwise the second. So yes, for a = ‘python’, a is truthy, so a or ‘world’ is ‘python’. For b which is empty string (falsy), it takes ‘world’.

So the outputs should be:

hello, python

hello, world

I think that’s right. Let me make sure there’s no syntax errors. The commas in the print statements add a space automatically. So the first print would combine ‘hello,’ and ‘python’ separated by a space, making ‘hello, python’. Same for the second one.

Yep, that seems correct.

Result
The code uses the logical or operator to determine which string to print. In Python, the or operator returns the first truthy value. Here’s the step-by-step explanation:

First Print Statement:

a = ‘python’ (a non-empty string, which is truthy).

a or ‘world’ evaluates to ‘python’ because a is truthy.

Output: hello, python

Second Print Statement:

b = ” (an empty string, which is falsy).

b or ‘world’ evaluates to ‘world’ because b is falsy.

Output: hello, world

Output:
hello, python
hello, world

原文链接：Python Logical OR Operator Usage Explained