Splitting long line printed to screen the right way in python - python

This might be a silly question but I'd like to know how other people handle this or if there's a standard/recommended way of going about it.
Below are two approaches to splitting a long text line when printing it to screen in python. Which one should be used?
Option 1
if some_condition: # Senseless indenting.
if another condition: # Senseless indenting.
print 'This is a very long line of text that goes beyond the 80\n\
character limit.'
Option 2
if some_condition: # Senseless indenting.
if another condition: # Senseless indenting.
print 'This is a very long line of text that goes beyond the 80'
print 'character limit.'
I personally find Option 1 ugly but Option 2 seems like it would go against the pythonic way of keeping things simple by using a second print call.

One way to do it can be with parenthesis:
print ('This is a very long line of text that goes beyond the 80\n'
'character limit.')
Of course, there are several ways of doing it. Another way (as suggested in comments) is the triple quote:
print '''This is a very long line of text that goes beyond the 80
character limit.'''
Personally I don't like that one much because it seems like breaking the indentation, but that's just me.

If you have a long string and want to insert line breaks at appropriate points, the textwrap module provides functionality to do just that. Ex:
import textwrap
def format_long_string(long_string):
wrapper = textwrap.TextWrapper()
wrapper.width = 80
return wrapper.fill(long_string)
long_string = ('This is a really long string that is raw and unformatted '
'that may need to be broken up into little bits')
print format_long_string(long_string)
This results in the following being printed:
This is a really long string that is raw and unformatted that may need to be
broken up into little bits

Related

Can anyone help me with what does this part of python code mean?

I would like to know what this small portion of code means, because it seems like in the file that the script creates it adds a line in the end and i believe it might be one of those symbols
opened_file.write("%s\n" %user_input)
It writes a line. The content of user_input replaces the %s (see string interpolation in the docs) and \n is the newline character - after user_input.
Here is a good description of the different "inserting data into strings" methods, including % interpolation (which is now considered outdated):
https://realpython.com/python-string-formatting/

Formatting text that is meant to be replaced

This is a rather generic question, but I have a textfile that I want to edit using a script.
What are some ways to format text, so that it will visually stand out but still be recognized by my script?
It works fine when I use text_to_be_replaced, but it is hard to find when you have a large file.
Tried searching, and it seems that the common ways are:
%text_to_be_replaced%
<text_to_be_replaced>
$(text_to_be_replaced)
But maybe there is a commonly used/widely accepted way to format text for visibility?
The language the script is written in is python, if that matters... but I'm looking for a more-or-less generic soluting which will work 90% of the time.
I'm not aware of any generic standard here, but if it's meant to be replaced, you can use the new string formatting method as follows:
string = 'some text {add_text_here} some more text'
Then to replace it when you need to:
value = 'formatted'
string = string.format(add_text_here=value)
Now print it out:
>>> string
'some text formatted some more text'
In fact, this quite neat at the addition of curly {brackets} around the text that needs to be replaced also may make it stand out a little.
At first I thought that {{curly braces}} would be fine, but than I went with $ALLCAPS.
First of all, caps really stands out, while lowercase may be confused with the rest of the code.
And while it $REALLYSTANDSOUT, it shouldn't cause any problems, since it's just a "bookmark" in a text file, and will be replaced with the appropriate stuff determined by the script.

Python - Remove Last Line From String

I'm trying to capture and manipulate data within a Telnet session using telnetlib, things are going fairly well, however my newbness with Python is causing me some headache.
My issue is pretty straight forward, I am able to capture and display the data I want (So far) however I just seem to be cycling through errors whenever I try to remove the last line of data from the data I have captured. My code goes something like this:
... Snipped Boring Stuff ...
tn.write('command to gather data' + '\r')
data = tn.read_very_eager()
print data
... snipped more boring stuff ...
Pretty simple... So, how in the world would I remove the last line of data from either tn.read_very_eager() or data() ?
Any direction would be awesome... Sorry for the really simple question, but the stuff I've read and tried so far have done nothing but frustrate me, my keyboard can't take much more abuse :)
You can remove the last line of a string like this:
def remove_last_line_from_string(s):
return s[:s.rfind('\n')]
string = "String with\nsome\nnewlines to answer\non StackOverflow.\nThis line gets removed"
print string
string = remove_last_line_from_string(string)
print '\n\n'+string
The output will be:
>>>
String with
some
newlines to answer
on StackOverflow.
This line gets removed
String with
some
newlines to answer
on StackOverflow.
>>>

Own pretty print option in python script

I'm outputting pretty huge XML structure to file and I want user to be able to enable/disable pretty print.
I'm working with approximately 150MB of data,when I tried xml.etree.ElementTree and build tree structure from it's element objects, it used awfully lot of memory, so I do this manually by storing raw strings and outputing by .write(). My output sequence looks like this:
ofile.write(pretty_print(u'\
\t\t<LexicalEntry id="%s">\n\
\t\t\t<feat att="languageCode" val="cz"/>\n\
\t\t\t<Lemma>\n\
\t\t\t\t<FormRepresentation>\n\
\t\t\t\t\t<feat att="writtenForm" val="%s"/>\n\
\t\t\t\t</FormRepresentation>\n\
\t\t\t</Lemma>\n\
\t\t\t<Sense>%s\n' % (str(lex_id), word['word'], '' if word['pos']=='' else '\n\t\t\t\t<feat att="partOfSpeech" val="%s"/>' % word['pos'])))
inside the .write() I call my function pretty_print which, depending on command line option, SHOULD strip all tab and newline characters
o_parser = OptionParser()
# ....
o_parser.add_option("-p", "--prettyprint", action="store_true", dest="pprint", default=False)
# ....
def pretty_print(string):
if not options.pprint:
return string.strip('\n\t')
return string
I wrote 'should', because it does not, in this particular case it does not strip any of the characters.
BUT in this case, it works fine:
for ss in word['synsets']:
ofile.write(pretty_print(u'\t\t\t\t<Sense synset="%s-synset"/>\n' % ss))
First thing that came on my mind was that there might be some issues with the substitution, but when i print passed string inside the pretty_print function it looks perfectly fine.
Any suggestiones what might cause that .strip() does not work?
Or if there is any better way to do this, I'll accept any advice
Your issue is that str.strip() only removes from the beginning and end of a string.
You either want str.replace() to remove all instances, or to split it into lines and strip each line, if you want to remove them from the beginning and end of lines.
Also note that for your massive string, Python supports multi-line strings with triple quotes that will make it a lot easier to type out, and the old style string formatting with % has been superseded by str.format() - which you probably want to use instead in new code.

using an alternative string quotation syntax in python

Just wondering...
I find using escape characters too distracting. I'd rather do something like this (console code):
>>> print ^'Let's begin and end with sets of unlikely 2 chars and bingo!'^
Let's begin and end with sets of unlikely 2 chars and bingo!
Note the ' inside the string, and how this syntax would have no issue with it, or whatever else inside for basically all cases. Too bad markdown can't properly colorize it (yet), so I decided to <pre> it.
Sure, the ^ could be any other char, I'm not sure what would look/work better. That sounds good enough to me, tho.
Probably some other language already have a similar solution. And, just maybe, Python already have such a feature and I overlooked it. I hope this is the case.
But if it isn't, would it be too hard to, somehow, change Python's interpreter and be able to select an arbitrary (or even standardized) syntax for notating the strings?
I realize there are many ways to change statements and the whole syntax in general by using pre-compilators, but this is far more specific. And going any of those routes is what I call "too hard". I'm not really needing to do this so, again, I'm just wondering.
Python has this use """ or ''' as the delimiters
print '''Let's begin and end with sets of unlikely 2 chars and bingo'''
How often do you have both of 3' and 3" in a string

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