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Exclude the characters before a given pattern


Exclude the characters before a given pattern

By : user2955319
Date : November 22 2020, 10:38 AM
may help you . Your current code is not working because your pattern is not matching what you think it is. Putting .* in a character set does not mean "zero or more characters". Instead, it means the characters . or * literally. Also, \. is treated as \ or ., not an escaped . (since . has no special meaning in a character set).
This means that your pattern is actually equivalent to:
code :
^.*[^\.*]
^       # The start of the string
.*      # Zero or more characters
[^\.*]  # A character that is not \, ., or *
>>> import re
>>> re.sub('[^.]*(.\..*)', r'\1', 'hello.world')
'o.world'
>>>
[^.]*  # Matches zero or more characters that are not .
(      # Starts a capture group
.      # Matches any character (save a newline).
\.     # Matches a literal .
.*     # Matches zero or more characters
)      # Closes the capture group
>>> import re
>>> re.search('[^.]*(.\..*)', 'hello.world').group(1)
'o.world'
>>>


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RegEx pattern to match a string between two characters, but exclude the characters

RegEx pattern to match a string between two characters, but exclude the characters


By : sundrymatter
Date : March 29 2020, 07:55 AM
Does that help Well, it all refers to the way you group items in the regular expression. Your solution is actually correct, you're just using the wrong index for matches. Try:
code :
$matches[1]
Find exactly two alphabetical characters [a-zA-Z] before a pattern, exclude all non word characters in between

Find exactly two alphabetical characters [a-zA-Z] before a pattern, exclude all non word characters in between


By : MIAO MEOW
Date : March 29 2020, 07:55 AM
To fix the issue you can do I need to find two alphabetical characters before a five digit number in a string. , Without converting to upper case, use:
code :
$subject =~ s/([a-z]{2})[^\da-z]+(\d{5})/$1$2/ig;
$regex = '(?i)([a-z]{2})[^\da-z]+(\d{5})';
$subject = ' _AB : 12342  onab :_ 12342 ';
($replaced = $subject) =~ s/$regex/
         { uc($1) . $2; }  /eg;
print $replaced . "\n";
How do I exclude certain characters from pattern matching in regex?

How do I exclude certain characters from pattern matching in regex?


By : Esteban
Date : March 29 2020, 07:55 AM
it fixes the issue I'm trying to implement my own version of atoi and so I want to check if my string contains non-numeric characters and handle the error, but I also also want the search pattern to exclude the + and - symbols (i.e + and - at the start of the string only are valid symbols). I currently have word.matches("^[+=][a-zA-Z]+"), but am not sure how to change it accordingly to fit my needs. Ex: 20e48 is invalid, 204-8 is invalid, +2048 is valid and so is -2048 , Here you go:
code :
public static void main(String[] args) {
    String pattern = "^[+-]?[0-9]+$";
    System.out.println("20e48".matches(pattern));
    System.out.println("204-8".matches(pattern));
    System.out.println("+2048".matches(pattern));
    System.out.println("-2048".matches(pattern));
    System.out.println("2048".matches(pattern));
}
false
false
true
true
true
^ => Starts
[+-] => Either plus or minus sign
? => Zero or one occurance
[0-9] => Any number
+ => One or more occurance
$ => End
Regex for repeatable pattern with exclude characters

Regex for repeatable pattern with exclude characters


By : Zaydh Nsangu
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further Tried different variations but couldn't found one that would be aplicable for my requirements. I need regex for the following case: , Would something like work? -> ^[a-zA-Z]+(\.[a-zA-Z]+)*$
How to match specifics characters and exclude them when they follows a pattern

How to match specifics characters and exclude them when they follows a pattern


By : user2739522
Date : March 29 2020, 07:55 AM
Hope this helps I'm currently trying to clean some data in a csv in python. But I have problem with my quotes in my csv, so I hope you can help me fix it with regex. , Using positiv lookahead and lookbehind:
code :
import re

s='"""My name";"";"is";""Hello ; World"";"";'                          

In: re.sub(r'(?<=[^;"])"+|"+(?=[^;"])',r'@',s)                             
Out: '@My name@;"";@is@;@Hello ; World@;"";'
(?<=[^;"])"+    matches quotes not preceeded by other quotes or ;
 "+(?=[^;"])    matches quotes not followed by other quotes or ;
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