Removing links from a reddit comments using python and regex [closed] - python

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I want to remove links in the format Reddit uses
comment = "Hello this is my [website](https://www.google.com)"
no_links = RemoveLinks(comment)
# no_links == "Hello this is my website"
I found a similar question about the same thing, but I don't know how to translate it to python.
I am not that familiar with regex so I would appreciate it if you explained what's happening.

You could do the following:
import re
pattern = re.compile('\[(.*?)\]\(.*?\)')
comment = "Hello this is my [website](https://www.google.com)"
print(pattern.sub(r'\1', comment))
The line:
pattern = re.compile('\[(.*?)\]\(.*?\)')
creates a regex pattern that will search for anything surrounded by square brackets, followed by anything surrounded by parenthesis, the '?' indicates that they should match as little text as possible (non-greedy).
The function sub(r'\1', comment) replaces a match by the first capturing group in this case the text inside the brackets.
For more information about regex I suggest you read this.

Related

Python check string pattern follows xxxx-yyyy-zzzz [closed]

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I am trying to build a check for strings that allows a pattern "xxxx-yyyy-zzzz". The string needs to have three blocks seperated by "-". Each block can contain "a-z", "A-Z", "_" (underscore) and "." (dot).
This is what I got to now:
file_name: str = "actors-zero-This_Is_Fine.exe.yml"
ab = re.compile("^([A-Z][0-9])-([A-Z][0-9])-([A-Z][0-9])+$")
if ab.match(file_name):
pass
else:
print(f"WARNING wrong syntax in {file_name}")
sys.exit()
Output is:
WARNING wrong name in actors-zero-This_Is_Fine.exe.yml
If I understand the question correctly, you want 3 groups of alphanumerical characters (plus .) separated by dashes:
Regex for this would be ^([\w.]+)-([\w.]+)-([\w.]+)$
^ matches the start of a string
Then we have 3 repeating groups:
([\w.]+) will match letters, numbers, underscores (\w) and dots (.) at least one time (+)
We make 3 of these, then separate each with a dash.
We finish off the regex with a $ to match the end of the string, making sure you're matching the whole thing.
What exactly is your question?
This looks alright so far. Your file name returns the warning because you have not specified the underscores in the third "block".
Instead of ([A-Z][0-9]). you could use character classes:
Like so: ^([\w.]+)-([\w.]+)-([\w.]+)$
Generally, I found the chapter in Automate The Boring Stuff on regex Pattern matching very concise and helpful:
https://automatetheboringstuff.com/2e/chapter7/
You will find the above table in this chapter also.

Matching pattern with regex: S(n,n+1) [closed]

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I am trying to match the following pattern
sn,n+1
where n is an integer. Examples include
s1,2 s3,4
Right now I know how to match the following: sn,n
(for example s1,1) with regex. The syntax I use for this is s(\d+),\1
Is it possible to do something like the following? s(\d+),\1+1
More detail on my specific problem (these details aren't necessarily relevant to the solution! But I am including them anyway), I am using CST, an electromagnetic simulator that supports regex for sorting s-parameter data. With a high port count, it is cumbersome to manually select isolation between ports. So I want to use a regex in the above way.
Regex can not do arithmetic but python does. You can find all matching patterns in your string and filter them later with python. This might help:
Regex
import re
string= 's1,2 test s2,3 , test test s12,12'
pattern = 's\d+,\d+'
pattern_list = re.findall(pattern, string)
print(pattern_list)
['s1,2', 's2,3', 's12,12']
Filtering with Python
result_list = [i for i in pattern_list if int(i.split(',')[0].split('s')[1]) + 1 == int(i.split(',')[1]) ]
print(result_list)
['s1,2', 's2,3']
Basically, it finds all patterns by using regex then python checks the patterns that fits to sn,n+1

Find a part of a string using python? [closed]

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For example:
string = "abcdefghi"
separated = "abc" + x + "ghi"
x = ???
I want to find x, using any string.
x=re.search('(?<=abc).*(?=ghi)','abcdefghi').group(0)
print(x)
output
def
Explanation
Regex
(?<=abc) #Positive look behind. Start match after abc
.* #Collect everything that matches the look behind and look ahead conditions
(?=ghi) #Positive look ahead. Match only chars that come before ghi
re.search documentation here.
A Match Object is returned by re.search. A group(0) call on it would return the full match. Detail on Match Object can be found here.
Note:
The regex is aggressive so would match/return defghixyz in abcdefghixyzghi.
See demo here.

How to match the pattern using re using the commas? [closed]

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How do I match the following pattern using re?
2016-02-13 02:00:00.0,3525,http://www.heatherllindsey.com/2016/02/my-husband-left-his-9-5-job-for-good-it.html,158,0,2584490
I used python's split() function to separate the attributes out but as the data is huge, the process is getting killed due to memory errors.
If you put the long version of string it would be better.
So how can you make it ? That is the answer:
import re
str = "2016-02-13 02:00:00.0,3525,http://www.heatherllindsey.com/2016/02/my-husband-left-his-9-5-job-for-good-it.html,158,0,2584490"
pattern = re.compile("(.*?),", re.DOTALL) #we use re.DOTALL to continue splitting after endlines.
result = pattern.findall(str) #we can't find the last statement (2584490) because of the pattern so we will apply second process
pattern = re.compile("(.*?)", re.DOTALL)
str2 = str[-50:-1]+str[-1] #we take last partition of string to find out last statement by using split() method
result.append(str2.split(",")[-1])
print result
It works...

Regex not working in python script [closed]

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for some reason when I get regex to get the number i need it returns none.
But when I run it here http://regexr.com/38n3o it works
the regex was designed to get the last number of the ip so it can be removed
lanip=74.125.224.72
notorm=re.search("/([1-9])\w+$/g", lanip)
That is not how you define a regular expressions in Python. The correct way would be:
import re
lanip="74.125.224.72"
notorm=re.search("([1-9])\w+$", lanip)
print notorm
Output:
<_sre.SRE_Match object at 0x10131df30>
You were using a javascript regex style. To read more on correct python syntax read the documentation
If you want to match the last number of an IP use:
import re
lanip="74.125.224.72"
notorm=re.search("(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)", lanip)
print notorm.group(4)
Output:
72
Regex used from http://www.regular-expressions.info/examples.html
Your example did work in this scenario, but would match a lot of false positives.
What is lanip's type? That can't run.
It needs to be a string, i.e.
lanip = "74.125.224.72"
Also your RE syntax looks strange, make sure you've read the documentation on Python's RE syntax.

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