all Python 3Built-in functionsterm

bin

numbers

Converts an integer to its binary string representation with the '0b' prefix. Negative numbers: bin(-5) → '-0b101'.

Syntax

bin(x)

The result is a string, not a number — arithmetic on it makes no sense, and int(s, 2) converts back. Negative values get a leading minus sign in front of the magnitude; this is not two's-complement machine representation. The argument must be an integer (or expose __index__), a float raises TypeError, and for a fixed-width value without the 0b prefix use the b format code instead.

Examples

print(bin(10))   # → 0b1010
print(bin(255))  # → 0b11111111
print(bin(-5))   # → -0b101
print(bin(0))    # → 0b0
print(int(bin(42),2))  # → 42

See also

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