python读写二进制文件的方法
本文实例讲述了python读写二进制文件的方法。分享给大家供大家参考。具体如下：
初学python，现在要读一个二进制文件，查找doc只发现 file提供了一个read和write函数，而且读写的都是字符串，如果只是读写char等一个字节的还行，要想读写如int,double等多字节数 据就不方便了。在网上查到一篇贴子，使用struct模块里面的pack和unpack函数进行读写。下面就自己写代码验证一下。
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2
3
4
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>>>
from
struct
import
*
>>>
file
=
open
(r
"c:/debug.txt"
,
"wb"
)
>>>
file
.write(pack(
"idh"
,
12345
,
67.89
,
15
))
>>>
file
.close()
|
接着再将其读进来
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7
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>>>
file
=
open
(r
"c:/debug.txt"
,
"rb"
)
>>> (a,b,c)
=
unpack(
"idh"
,
file
.read(
8
+
8
+
2
))
>>> a,b,c
(
12345
,
67.890000000000001
,
15
)
>>>
print
a,b,c
12345
67.89
15
>>>
file
.close()
|
在操作过程中需要注意数据的size
注意 wb,rb中的b字，一定不可以少
方法1：
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myfile
=
open
(
'c:\\t'
,
'rb'
)
s
=
myfile.read(
1
)
byte
=
ord
(s)
#将一个字节 读成一个数
print
hex
(byte)
#转换成16进制的字符串
|
方法2
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2
3
4
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import
struct
myfile
=
open
(
'c:\\t'
,
'rb'
).read(
1
)
print
struct.unpack(
'c'
,myfile)
print
struct.unpack(
'b'
,myfile)
|
写入
To open a file for binary writing is easy, it is the same way you do for reading, just change the mode into “wb”.
file = open("test.bin","wb")
But, how to write the binary byte into the file?
You may write it straight away with hex code like this:
file.write("\x5F\x9D\x3E") file.close()
Now, check it out with hexedit,
hexedit test.bin
You will see this:
00000000 5F 9D 3E _.> 00000020 00000040
Now, open the file to append more bytes:
file = open("test.bin","ab")
What if I want to store by bin value into a stream and write it one short?
s ="\x45\xF3" s = s + "%c%c" % (0x45,0xF3) file.write(s) file.close()
Any convenient ways if I can obtained a hex string, and want to convert it back to binary format?
Yes, you just need to import binascii
import binascii hs="5B7F888489FEDA" hb=binascii.a2b_hex(hs) file.write(hb) file.close()
希望本文所述对大家的Python程序设计有所帮助。