[Tutor] Newline issues

[Alex Kleider]

On 2020-05-11 11:36, boB Stepp wrote:
> My end goal:  Get my Google contacts into Mutt.

Are you trying to create a "~/.muttalias" file?
If so, I can send you some code that accomplishes this (using a gmail 
exported contacts.csv file as input.)
Let me know.
Alex

> 
> 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?