Python将'N'字节数据写入二进制文件

Question

I have following data in Excel sheet, 1st column is number of bytes, 2nd column is its data (dat is in decimal,hex,ip address format)

Question is how to write these into binary file, like in 1 bytes data,write 0x01,then 2 bytes data, write 0xAABB,then in 4 bytes data,write 10080000(dec)..etc even ip address in 4 bytes,write 10.65.84.8

Questions: 1)is it required to convert all data to one format (ie decimal or hex) ? 2) are there inbuilt functions which gives write(num_of_bytes, value) ?

File.xls

Number of bytes Data

1             0x01 (hex)
2             0xAABB
4             10080000
2             100
4             18181818 (decimal)
4             10.65.84.8(ip address)

i am new to python and have done following to read data from Excel(cvs) sheet

def open_file():
    book = xlrd.open_workbook('file.csv') 
    # get the first worksheet
    first_sheet = book.sheet_by_index(0)

    # read a cell
    cell = first_sheet.cell(0,0)
    num_rows = first_sheet.nrows 
    num_cols = first_sheet.ncols 

    for m in range(0, num_rows):
        for n in range(0, num_cols):
            cell = first_sheet.cell(m,n)
            print 'cell value %d',cell.value

Answer 1

You can use struct , pack and unpack to read and write binary data, the best solution I found and the cleanest is to handle data in hex() format. Also pay attention to the indianness of your machine, when you will write and read, is it on the same machine!

Cheers,