Python Pocket Reference

Built-in Types and Operators

Operators and Precedence

Table 1-1 lists Python’s expression operators. Operators in lower cells of the table have higher precedence (i.e., bind tighter, when used in mixed expressions without parentheses).

Table 1-1. Operators and Precedence

Operators	Description
X or Y, lambda args: expr	Logical ‘or’ (Y is only evaluated if X is false), anonymous function
X and Y	Logical ‘and’ (Y is only evaluated if X is true)
not X	Logical negation
X < Y, X <= Y, X > Y, X >= Y, X == Y, X <> Y, X != Y, X is Y, X is not Y, X in S, X not in S	Comparison operators, equality operators, identity tests, sequence membership
X | Y	Bitwise ‘or’
X ^ Y	Bitwise ‘exclusive or’
X & Y	Bitwise ‘and’
X << Y, X >> Y	Shift X left or right by Y bits
X + Y, X — Y	Addition/concatenation, subtraction
X * Y, X / Y, X % Y	Multiply/repetition, divide, remainder/format
-X, +X, ~X, X**Y	Unary negation, identity, bitwise complement, power
X[i], X[i:j], X.attr, X( . . . )	Indexing, slicing, qualification, function calls
( . . . ), [ . . . ], { . . . }, ` . . . `	Tuple, list, dictionary, conversion to string

Operations by Category

All types support comparisons and boolean operations.

• True means any non-zero number, or any non-empty collection object (list, dictionary, etc.). The special object None is false.

• Comparisons return 1 or 0 and are applied recursively in compound objects as needed to determine a result.

• Boolean and and or operators stop as soon as a result is known (short-circuit) and return an operand object.

Table 1-2. Comparisons ...