Question

I transport data from command line to python. And I want to convert from string (command line) to tuple (python). But I have problem with \ charactor.

In command line, I using:

C:\>python music.py -a variable="?=="

In python:

#convert variable to array 
variable_array = variable.split("==")
#convert to tuple
variable_tuple = tuple(variable_array)

I get variable_tuple = (“?”,””)

The result what I need is variable_tuple = (“\?”,””)

When using

C:\>python music.py -a variable="\?=="

The result is variable_tuple = (“\\?”,””)

How can I transport data from command line to get tuple (“\?”,””) in python? I need backslash for “?”

Answer 1

'\\?' is a string with one backslash character and a question mark.
Using list is a convenient trick for spliting a string into characters. For example:

In [34]: list('\\?')
Out[34]: ['\\', '?']

shows '\\?' is composed of 2 characters, not 3. And if you print it:

In [35]: print('\\')
\

you see it prints as just one backslash character. The double backslash, '\\', is an escape sequence.

---

Note also that when you print a tuple, you get the repr of its contents:

In [36]: print(tuple('\\?'))
('\\', '?')

---

'\?' is the exact same string as '\\?' in Python. They are simply different ways of representing the same string:

In [38]: list('\?')
Out[38]: ['\\', '?']

In [39]: list('\\?')
Out[39]: ['\\', '?']    

In [42]: '\?' is '\\?'
Out[44]: True