python struct

   calcsize(fmt)
      　　fmt爲格式化字符串,返回格式化字符串所佔字節大小
　　　　　 好比fmt=">5sH" calcsize(fmt)　輸出7 5s２個字節，H2個字節


    (fmt, v1, v2, ...)
　　　　按fmt將v1,v2格式化存儲並返回一個字符串

   (fmt, buffer, offset, v1, v2, ...)
        pack完的數據存放到buffer中偏移offset的位置，offset必須指定

    (fmt, string)
        Unpack the string containing packed C structure data, according to fmt.
        Requires len(string) == calcsize(fmt).

    unpack_from(fmt,content,offset)
　　　　　　按fmt中格式從context偏移offset處解析出tuple對象packpack_intounpack

　　　　　　Unpack the buffer, containing packed C structure data, according to fmt,
　　　　　　 starting at offset. Requires len(buffer[offset:]) >= calcsize(fmt).
　　

搬磚整理

 

fmt:來自python幫助文檔

 

The optional first format char indicates byte order, size and alignment: 

  @: native order, size & alignment (default)
  =: native order, std. size & alignment
  <: little-endian, std. size & alignment
  >: big-endian, std. size & alignment
  !: same as >

 

import struct

#----------------------------------------------------------------------
def main():
    """"""
    fmt =     ">5sH"
    pbuf  = struct.pack(fmt,"11111",1)
    open("1.txt","wb").write(pbuf)

    
    readbuf=open("1.txt","rb").read()
    tp=struct.unpack(fmt,readbuf)

    for i in tp:
        print i


if __name__ == '__main__':

    main()

輸出: