unpack_from(fmtbufferoffsetunpacks the contents of buffer object according to the format string in fmt starting at offset offset returns tuple of the unpacked values calcsize(fmtcalculates the size in bytes of the structure corresponding to format string fmt struct objects the struct module defines class struct that provides an alternative interface for packing and unpacking using this class is more efficient because the format string is only interpreted once struct(fmtcreates struct instance representing data packed according to the given format code an instance of struct has the following methods that work exactly the same as their functional counterparts described in the previous sectionmethod description pack( packs values into byte string pack_into(bufferoffsetv packs values into buffer object unpack(bytesunpacks values from byte string unpack_from(bufferoffsetunpacks values from buffer object format the format code being used size the size in bytes of the format format codes the format strings used in the struct module are sequence of characters with the following interpretationsformat type python type ' ' ' ' '?' ' ' ' ' ' ' 'qpad byte char signed char unsigned char _bool ( short unsigned short int unsigned int long unsigned long long long unsigned long long no value string of length integer integer boolean integer integer integer integer integer integer long long continues lib fl ff