Why Does \'1\' in \'11\' == True Evaluate to False in Python?

Python: Operator Precedence Confusion with 'in' and Comparison Operators

In Python, comparing sequence membership and equality can lead to unexpected results due to the equal precedence of the 'in' and comparison operators. When encountered in an expression without parentheses, these operators are evaluated from left to right.

For example:

'1' in '11' == True  # Evaluates to False

This expression is interpreted as:

('1' in '11') and ('11' == True)

Since '11' is not equal to True, the entire expression evaluates to False. To achieve the intended result (True), parentheses are required:

'1' in '11' == True  # Evaluates to True

However, if parentheses are placed around the opposite operand:

'1' in ('11' == True)  # TypeError

a TypeError is raised because '11' equals True, which is a boolean value and therefore not iterable. To avoid this error, ensure that the 'in' operator is used with an iterable object.

Understanding operator precedence and chaining in Python is crucial to write code that behaves as expected. Operators with equal precedence are evaluated from left to right, and chaining allows you to perform multiple evaluations in a single line. By carefully considering operator precedence and chaining, you can avoid unexpected results and write more efficient code.

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