all Python 3socketfunction

socket.ntohs()

address and byte-order conversion

Converts a 16-bit integer from network byte order (big-endian) to host order; the inverse of htons().

Syntax

socket.ntohs(x) -> int

It applies to a number, not to bytes: the two port bytes from a header are first turned into an int and only then swapped. int.from_bytes(data, 'big') or struct.unpack('!H', data) is shorter. Since 3.10 a value above 65535 raises OverflowError; before that the high bits were dropped with only a DeprecationWarning and the bug stayed hidden. Since 3.14 a negative value raises ValueError.

Examples

import socket, sys
data = (8080).to_bytes(2, 'big')  # порт в заголовке пакета
print(socket.ntohs(int.from_bytes(data, sys.byteorder)))  # → 8080
print(int.from_bytes(data, 'big'))  # → 8080

# Python 3.10+
import socket
socket.ntohs(70000)  # → OverflowError

See also

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