具有复杂参数的python函数

Question

I have a function in a python code whose argument is as follows:

save_geometry(r"""C:\Users\User0\Documents\test.txt """)

I want to modify the argument and be able to save to a different path with a different filename:

filename = "geometries.txt "
filepath = "D:/AllData/"
filefullpath = filepath + filename

Could someone help me how I should pass filefullpath to save_geometry ? If there were no r in the argument of save_geometry , it would be easy. But I don't know how to deal with this r .

Answer 1

The r"" construct just tells Python that whatever's in the string should be interpreted as raw data.

"qw\n" == 'qw\n'
r"qw\n" == 'qw\\n'.

It's used because the "\\" path separator is also used for newlines and such. You can skip it when putting in the argument; save_geometry(filefullpath) should do what you expect.

Answer 2

Note that the canonical way of putting together paths is os.path.join

path = os.path.join("D:\\", "AllData", "geometries.txt")

User3757614's answer addresses your concern of the raw string notation, but succinctly all the r"" notation does is tell Python that the following string should not treat \\ as an escape character, but as a literal backslash. This is important since "C:\\new folder" is actually

C:
ew folder

Since \\n is a newline.

Answer 3

You cans use the os module to split your string into a folder path and file name.

eg

import os
pathname = os.path.dirname('C:\Users\User0\Documents\test.txt')  #C:\Users\User0\Documents
filename = os.path.basename('C:\Users\User0\Documents\test.txt')  #test.txt

Though you'll need to modify your path string because your \\ s will be interpreted and newline bytes