[Tutor] Newline issues

[boB Stepp]

My end goal:  Get my Google contacts into Mutt.

My process so far:  Export contacts from Google Contacts as a vCard file.
Use VObject (http://eventable.github.io/vobject/) to parse the vCard file.  But
the file that exports from Google-land has some issues that causes
VCard to throw parsing exceptions.  I have identified in contacts.vcf
(the vCard file) the problems that cause the parsing exceptions.  (1) All
address lines have a duplicate entry tacked onto the end with embedded
'\n's.  (2) In the notes entry there are embedded '\n's.

So I first was going to address the embedded '\n's by using a
s.replace('\n', ' ') approach.  This failed.  So I wrote the following test
program to try to understand what was happening:

with open("test.txt") as f:
    for line in f:
        print(line)
        print(line.replace("\n", ""))
        print(line.replace(r"\n", ""))
        print(line.replace("\\", ""))

test.txt (an actual excerpt from a fake Google contact export):

NOTE:This is a test contact to see all fields.\n2nd line\:  Did not fill in
  \"Chat\" field.\n3rd line\:  Did not fill in \"Internet call\" field.\n4t
 h line\:  I will keep typing until the editor flows this text to the follo
 wing line.  It will now happen.\n1st custom label: My first custom field\n
 2nd custom label: My second custom field\n3rd custom label: My third custo
 m field

Running the program on this file produced the following output:

NOTE:This is a test contact to see all fields.\n2nd line\:  Did not fill in

NOTE:This is a test contact to see all fields.\n2nd line\:  Did not fill in
NOTE:This is a test contact to see all fields.2nd line\:  Did not fill in

NOTE:This is a test contact to see all fields.n2nd line:  Did not fill in
[-- snipped remaining output --]

The first line appears as is.

The second had no effect on replacing the apparent '\n' characters.

The third line shows that using raw strings *did* remove the apparent '\n'
characters.

Finally, the fourth line (removing the forward slashes) did so leaving all
associated 'n's.

My conclusion is that in the file the apparent newline characters are
actually *two* characters, '\' and 'n'.

Now we get to my point of confusion.  When I copy and paste the text.txt
contents into a triple-quoted string variable in the interpreter I get
results I am not sure I understand:

3.7.5:  s = """
...     NOTE:This is a test contact to see all fields.\n2nd line\:  Did not fill in
...       \"Chat\" field.\n3rd line\:  Did not fill in \"Internet call\" field.\n4t
...      h line\:  I will keep typing until the editor flows this text to the follo
...      wing line.  It will now happen.\n1st custom label: My first custom field\n
...      2nd custom label: My second custom field\n3rd custom label: My third custo
...      m field
...     """
3.7.5:  s
'\nNOTE:This is a test contact to see all fields.\n2nd line\\:  Did not fill in\n  "Chat" field.\n3rd line\\:  Did not fill in "Internet call" field.\n4t\n h line\\:  I will keep typing until the editor flows this text to the follo\n wing line.  It will now happen.\n1st custom label: My first custom field\n\n 2nd custom label: My second custom field\n3rd custom label: My third custo\n m field\n'
3.7.5:  print(s)

NOTE:This is a test contact to see all fields.
2nd line\:  Did not fill in
  "Chat" field.
3rd line\:  Did not fill in "Internet call" field.
4t
 h line\:  I will keep typing until the editor flows this text to the follo
 wing line.  It will now happen.
1st custom label: My first custom field

 2nd custom label: My second custom field
3rd custom label: My third custo
 m field

I am not certain how just entering "s" in the interpreter will display in
your MUAs, but in my display it as if the natural line breaks have
vanished with the exception of the manual one I entered immediately after
the first triple-quote and what I entered just before the final
triple-quote.

Finally, the print(s) apparently treats those '\' + 'n' characters as a
genuine newline.  Would someone please clarify the interpreter behavior for
me and the difference from what I observed with the actual file?

-- 
Wishing you only the best,

boB Stepp