在Python中串联字符串

Question

How can I properly concatenate a variable inside an string in Python?

I am trying to pass service in "Database Connections\\\\'service'.sde" and (r"C:\\GIS\\Maps\\'.+service+.'.mxd")

service ="Electric"
sde = "Database Connections\\'service'.sde"
mxd = arcpy.mapping.MapDocument(r"C:\GIS\Maps\'.+service+.'.mxd")

so the output looks like

sde = "Database Connections\\Electric.sde"
mxd = arcpy.mapping.MapDocument(r"C:\GIS\Maps\Electric.mxd")

Answer 1

I think a better way to do this is using os.path.join :

import os
mxd = arcpy.mapping.MapDocument(os.path.join(*"C:\\GIS\\Maps\\".split('\\') 
                                                    + ["{}.mxd".format(service)]))

Also, note that your back-slashes need to be escaped.

Answer 2

This is how Python's string concatenation works:

sde = "Database Connections\\" + service + ".sde"
mxd = arcpy.mapping.MapDocument("C:\\GIS\\Maps\\" + service + ".mxd")

Answer 3

An alternative which bypasses the issue of raw strings can't end with a single backslash :

r'C:\GIS\Maps\%s.mxd' % service

and

r'C:\GIS\Maps\{}.mxd'.format(service)

both work fine, dodging the issue with the string ending in a backslash.