Question

我熟悉C ++，我尝试开始使用python。

从串行线我设法用python接收一串二进制字符（不是ASCII），比方说rx'缓冲区'。我必须将此字符串拆分为不同的字段，我使用的方法是：

stx = (rx[0]) 
ctl = (rx[1])
node = (rx[2])
cTime = (rx[3:6])
nTime = (rx[7:10])
etx = (rx[11])

（目前我还没有找到一种方法来定义C ++的结构）。

现在我的问题是通常使用以下方式将这些字段打印为ASCII：

print "%d-%d-%d-%ld-%ld-%d" % (stx,ctl,node,cTime,nTime,etx)

错误消息是：

TypeError: %d format: a number is required, not str

我已经尝试过转换不同格式的字段，但没有任何作用。有人可以帮帮我吗？

Answer 1

You probably need to convert your variables to numbers by float(stx) (or int) but if you only want to print them just use %s instead of %d which expects the variable to be a double (meaning float).

For example:

rx = '1' * 12
stx = float(rx[0]) 
ctl = float(rx[1])
node = float(rx[2])
cTime = float(rx[3:6])
nTime = float(rx[7:10])
etx = float(rx[11])

print "%d-%d-%d-%ld-%ld-%d" % (stx,ctl,node,cTime,nTime,etx)

prints

1-1-1-111-111-1

or with strings you change the last line:

print "%s-%s-%s-%s-%s-%s" % (stx,ctl,node,cTime,nTime,etx)

In case you are dealing with raw binary data you might need the builtin struct module.

As far as I understand it (given you haven't posted an actual content and desired output I cannot verify it) you might want something like:

import struct
stx, ctl, node, cTime, nTime, etx = struct.unpack('fffddf', rx)

That would expect 3 floats, 2 doubles and then again 1 float. If you have integer or other datatypes you must edit the fffddf string. See the format types of struct

Answer 2

Brrr awfull

我终于找到了这种简单功能的一种方法：

> print int(stx.encode('hex'),16),int(ctl.encode('hex'),16),
> int(node.encode('hex'), 16), int(cTime.encode('hex'), 16),
> int(nTime.encode('hex'), 16),  int(etx.encode('hex'), 16)

不确定我会不会喜欢python

如何在ASCII二进制字段中打印

2 个答案: