[英]Converting character to int and vice versa in Python
I have an external app that appends the length of the packet at the start of the data. 我有一个外部应用程序,在数据的开头附加数据包的长度。 Something like the following code:
类似下面的代码:
x = "ABCDE"
x_len = len(x)
y = "GHIJK"
y_len = len(y)
test_string = chr(x_len) + x + chr(y_len) + y
#TODO:perform base64 encoding
In the client side of the code I need to be able to extract x_len and y_len and read x and y accrodingly. 在代码的客户端,我需要能够提取x_len和y_len并且可以读取x和y。
#TODO:perform base64 decoding
x_len = int(test_string[0])
x = test_string[:x_len]
I get the following error: ValueError: invalid literal for int() with base 10: '\\x05' 我收到以下错误:ValueError:int()的基数为10的无效文字:'\\ x05'
I assume the argument of int is in hex so I probbaly need to do some decoding before passing to the int. 我假设int的参数是十六进制的,所以我在传递给int之前需要做一些解码。 Can someone give me a pointer as to what function to use from decode or if there is any easier way to accomplish this?
有人可以给我一个指针,说明从解码中使用什么功能,或者有没有更简单的方法来完成这个?
You probably want ord()
, not int()
, since ord()
is the opposite operation from chr()
. 你可能想要
ord()
,而不是int()
,因为ord()
是与chr()
相反的操作。
Note that your code will only work for lengths up to 255
since that is the maximum chr()
and ord()
support. 请注意,您的代码仅适用于长度最大为
255
代码,因为这是最大的chr()
和ord()
支持。
t="ABCDE"
print reduce(lambda x,y:x+y,[ord(i) for i in t])
#output 335
usage of ord: it is used to convert character to its ascii values .. ord的用法:用于将字符转换为ascii值。
in some cases only for alphabets they consider A :1 --- Z:26 in such cases use 在某些情况下,他们只考虑字母A:1 --- Z:26在这种情况下使用
ord('A')-64
results 1 since we know ord('A')
is 65 ord('A')-64
结果1因为我们知道ord('A')
是65
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