True and False in Various Programming Languages

Language False True Short-Circuiting Logic And Short-Circuiting Logic Or Notes
LISP NIL T, anything but NIL (including 0) (and) (or) Most elegant in my opinion. NIL is the absence of a value. Anything but NIL is a value and thus true, including 0. Zero is a value too — but many languages disagree.
C 0 1, anything but 0 && || C is designed to be the portable assembly languages. Most hardware can only store values, not absence of values, so 0 is probably the best emulation of Lisp's NIL.
Perl undef, 0, 0.0, "" 1, anything but false && || Mix of Lisp's and C's true/false values: undef is like Lisp's NIL, although the valid number 0 and the valid empty string are considered false.
Unix Shell anything but 0 0 && || Programs usually return 0 (EXIT_SUCCESS) on success, non-zero on failure. The logic operators respect this.
Python None, 0, "", [], {} anything but false and or Source:
TI Basic? even numbers (0) odd numbers (-1) * + Not sure if this is TI-Basic. Older versions maybe? The LSB indicates the Boolean value.

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Modified Sun Mar 25 08:48:47 2007 generated Sun Mar 25 08:56:33 2007