ab = open("bonj.txt","w")
exec(f'''print("Hi I'm Mark\n", file=ab)
print("\tToday I'm tired", file=ab)
''')
ab.close()
I would absolutely need to use exec() to print some informations on a txt doc. The problem is that when I use exec(), I lost the possibility of put newlines or tabs on my text, and I dont understand why, could you help me ?
This is the error message that I receive : "SyntaxError: EOL while scanning string literal"
You just need to escape \n and \t properly
ab = open("bonj.txt","w")
exec(f'''print("Hi I'm Mark\\n", file=ab)
print("\\tToday I'm tired", file=ab)
''')
ab.close()
You need to prevent python from interpreting the \n early.
This can be done by specifying the string as a raw string, using the r prefix:
ab = open("bonj.txt","w")
exec(rf'''print("Hi I'm Mark\n", file=ab)
print("\tToday I'm tired", file=ab)
''')
ab.close()
Anyway, using exec is odd there, you would rather try to see if you can write your code as something like:
lines = ["Hi I'm Mark\n", "\tToday I'm tired"]
with open("bonj.txt", "w") as f:
f.write("\n".join(lines))
Note that you need to use "\n".join to obtain the same result as with print because print adds a newline by default (see its end="\n" argument).
Also, when handling files, using the context manager syntax (with open ...) is good practice.
Related
Sorry if this is a duplicate/basic question, I couldn't find any similar questions.
I have the following multiline string
my_txt = """
foo.exe\n
bar.exec\n
abab.exe\n
"""
(The newlines aren't actually written in my code, I put them there for clarity).
I want to match every file that ends with a .exe, (not .exec).
My regex was initially:
my_reg = re.compile(".+[.](?=exe$)")
my_matches = my_reg.finditer(my_txt)
I hoped that it would first find every character, go back until it found the ., and then check if the characters exe and a newline followed.
Only one match was found, and that was:
abab.exe.
I tried to mess around a bit, and changed the first line:
my_reg = re.compile(".+[.](?=exe$)",flags=re.MULTILINE).
This time, it successfully ran, returning
foo.
abab.
I thought re.MULTILINE wasn't supposed to interfere with the $ operator, or am I wrong about the $ operator/misusing something?
Thanks in advance!
You do need the multiline flag, otherwise $ will only match the absolute end of your input. You just need to match exe instead of using a lookahead:
my_reg = re.compile(".+[.]exe$", re.MULTILINE)
Output:
['foo.exe', 'abab.exe']
Demo
If you are trying to match the filename without the extension, you can put the period inside the lookahead:
my_reg = re.compile(r".+(?=\.exe$)", re.MULTILINE)
Output:
['foo', 'abab']
Demo
I have seen several related posts and several forums to find an answer for my question, but nothing has come up to what I need.
I am trying to use variable instead of hard-coded values in regex which search for either word in a line.
However i am able to get desired result if i don't use variable.
<http://www.somesite.com/software/sub/a1#Msoffice>
<http://www.somesite.com/software/sub1/a1#vlc>
<http://www.somesite.com/software/sub2/a2#dell>
<http://www.somesite.com/software/sub3/a3#Notepad>
re.search(r"\#Msoffice|#vlc|#Notepad", line)
This regex will return the line which has #Msoffice OR #vlc OR #Notepad.
I tried defining a single variable using re.escape and that worked absolutely fine. However i have tried many combination using | and , (pipe and comma) but no success.
Is there any way i can specify #Msoffice , #vlc and #Notepad in different variables and so later i can change those ?
Thanks in advance!!
If I did understand you the right way you'd like to insert variables in your regex.
You are actually using a raw string using r' ' to make the regex more readable, but if you're using f' ' it allows you to insert any variables using {your_var} then construct your regex as you like:
var1 = '#Msoffice'
var2 = '#vlc'
var3 = '#Notepad'
re.search(f'{var1}|{var2}|{var3}', line)
The most annoying issue is that you will have to add \ to escaped char, to look for \ it will be \\
Hope it helped
import re
lines = ["<http://www.somesite.com/software/sub/a1#Msoffice>",
"<http://www.somesite.com/software/sub1/a1#vlc>",
"<http://www.somesite.com/software/sub2/a2#dell>",
"<http://www.somesite.com/software/sub3/a3#Notepad>"]
for line in lines:
if re.search(r'\b(?:\#{}|\#{}|\#{})\b'.format('Msoffice', 'vlc', 'Notepad'), line):
print(line)
Output :
<http://www.somesite.com/software/sub/a1#Msoffice>
<http://www.somesite.com/software/sub1/a1#vlc>
<http://www.somesite.com/software/sub3/a3#Notepad>
I was trying to log a completion of a scheduled event I set to run on Django. I was trying my very best to make my code look presentable, So instead of putting the string into a single line, I have used a multiline string to output to the logger within a Command Management class method. The example as code shown:
# the usual imports...
# ....
import textwrap
logger = logging.getLogger(__name__)
class Command(BaseCommand):
def handle(self, *args, **kwargs):
# some codes here
# ....
final_statement = f'''\
this is the final statements \
with multiline string to have \
a neater code.'''
dedented_text = textwrap.dedent(final_statment)
logger.info(dedent.replace(' ',''))
I have tried a few methods I found, however, most quick and easy methods still left a big chunk of spaces on the terminal. As shown here:
this is the final statement with multiline string to have a neater code.
So I have come up with a creative solution to solve my problem. By using.
dedent.replace(' ','')
Making sure to replace two spaces with no space in order not to get rid of the normal spaces between words. Which finally produced:
this is the final statement with multiline string to have a neater code.
Is this an elegant solution or did I missed something on the internet?
You could use regex to simply remove all white space after a newline. Additionally, wrapping it into a function leads to less repetitive code, so let's do that.
import re
def single_line(string):
return re.sub("\n\s+", "", string)
final_statement = single_line(f'''
this is the final statements
with multiline string to have
a neater code.''')
print(final_statement)
Alternatively, if you wish to avoid this particular problem (and don't mine the developmental overhead), you could store them inside a file, like JSON so you can quickly edit prompts while keeping your code clean.
Thanks to Neil's suggestion, I have come out with a more elegant solution. By creating a function to replace the two spaces with none.
def single_line(string):
return string.replace(' ','')
final_statement = '''\
this is a much neater
final statement
to present my code
'''
print(single_line(final_statement)
As improvised from Neil's solution, I have cut down the regex import. That's one line less of code!
Also, making it a function improves on readability as the whole print statement just read like English. "Print single line final statement"
Any better idea?
The issue with both Neil’s and Wong Siwei’s answers is they don’t work if your multiline string contains lines more indented than others:
my_string = """\
this is my
string and
it has various
identation
levels"""
What you want in the case above is to remove the two-spaces indentation, not every space at the beginning of a line.
The solution below should work in all cases:
import re
def dedent(s):
indent_level = None
for m in re.finditer(r"^ +", s):
line_indent_level = len(m.group())
if indent_level is None or indent_level > line_indent_level:
indent_level = line_indent_level
if not indent_level:
return s
return re.sub(r"(?:^|\n) {%s}" % indent_level, "", s)
It first scans the whole string to find the lowest indentation level then uses that information to dedent all lines of it.
If you only care about making your code easier to read, you may instead use C-like strings "concatenation":
my_string = (
"this is my string"
" and I write it on"
" multiple lines"
)
print(repr(my_string))
# => "this is my string and I write it on multiple lines"
You may also want to make it explicit with +s:
my_string = "this is my string" + \
" and I write it on" + \
" multiple lines"
I'm really stumped as to why this doesn't work. All I want to do is removing zwsp (u200b), and newlines and extra spaces from content read from a file.
Ultimately, I want to write this out to a new file, which I have functional, just not in the desired format yet.
My input (a short test file, which has zwsp / u200b in it) consists of the following:
Australia 1975
Adelaide 2006 23,500
Brisbane (Logan) 2006 29,700
Brisbane II (North Lakes) 2016 29,000
Austria 1977
Graz 1989 26,100
Innsbruck 2000 16,000
Klagenfurt 2008 27,000
My code so is as follows:
input_file = open('/home/me/python/info.txt', 'r')
file_content = input_file.read()
input_file.close()
output_nospace = file_content.replace('\u200b' or '\n' or ' ', '')
print(output_nospace)
f = open('nospace_u200b.txt', 'w')
f.write(output_nospace)
f.close()
However, this doesn't work as I expect.
Whilst it removes u200b, it does not remove newlines or spaces. I have to test for absence of u200b by checking the output file produced as part of my script.
If I remove one of the operations, e.g. /u200b, like so:
output_nospace = file_content.replace('\n' or ' ', '')
...then sure enough the resulting file is without newlines or spaces, but u200b remains as expected. Revert back to the original described at the top of this post, and it doesn't remove u200b, newlines and spaces.
Can anyone advise what I'm doing wrong here? Can you chain list operations like this? How can I get this to work?
Thanks.
The result of code like "a or b or c" is just the first thing of a, b, or c that isn't considered false by Python (None, 0, "", [], and False are some false values). In this case the result is the first value, the zwsp character. It doesn't convey to the replace function that you're looking to replace a or b or c with ''; the replace code isn't informed you used 'or' at all. You can chain replacements like this, though: s.replace('a', '').replace('b', '').replace('c', ''). (Also, replace is a string operation, not a list operation, here.)
Based on this question, I'd suggest a tutorial like learnpython.org. Statements in Python or other programming languages are different from human-language sentences in ways that can confuse you when you're just starting out.
As indicated by #twotwotwo, the following implementation of a .replace chain solves the issue.
output_nospace = \
file_content.replace('\u200b', '').replace('\n', '').replace(' ', '')
Thanks so much for pointing me in the right direction. :)
Checking to see if it's possible to format a string reliably with base model prolog(no modules). I have the following code that I thought would work but doesn't:
hello(_) :-
write('\nEnter Name: '),
read(Name),
format('\nThe name you entered is: ~s', [Name]).
This throws the error if the user entered Bob. but works if the user entered "Bob". or 'Bob'.
ERROR: format/2: Illegal argument to format sequence ~s: _G7118
I have also tried replacing the format with writeq like:
hello(_) :-
write('\nEnter Name: '),
read(Name),
writeq(Name).
Which doesn't thrown an error but does just end up printing _L143 instead of Bob
(Too long for a comment)
Don't use read like this, as #lurker explains, it is not for entering "strings" or "text" or answers to questions altogether. Before even going down this road, ask yourself: "Why?"
The Prolog top level is your interactive command line prompt. It is not like in C or any other compiled language where you need to actually make your interpreter.
So, your hello/1 could look like this:
hello(Name) :-
format("~w~n", [Name]).
You still need to say hello("Bob") or hello('Bob') from the prompt, of course.
If you want to make your own interpreter on top of the Prolog top level, this is another thing altogether.
As other have said, read/1 reads only valid Prolog syntax. To read an arbitrary line of text using standard Prolog primitives, you would have to read the input character by character:
read_line(Cs) :-
get_code(C),
( C == 0'\n -> Cs = [] % end of line
; C == -1 -> Cs = [] % end of input
; Cs = [C|Cs1], read_line(Cs1)
).
As you are using SWI-Prolog, indicated by your use of format/2 and the (deleted by others) SWI-Prolog tag, you can also use
read_line(String) :-
current_input(Input),
read_string(Input, "\n", "\r", End, String).
Other systems have the same or similar predicates, but they are not standardized.