i want to find in text file names (ex. name.txt).
Could you please suggest me the regex expression to use in preg_match_all()?
I create some regex expression:
preg_match_all("/^[a-zA-Z0-9_.]+[.][a-zA-Z0-9]{1,3}$/", $string, $w);
But, always get an empty result.
just delete these symbols (^ and $) in you reg expression
This works for me:
preg_match_all("![a-zA-Z0-9_.]+[.][a-zA-Z0-9]{1,3}!", $string, $w);
^ - Matches the beginning of the string.
$ - Matches the end of the string.
If you file is placed in the text you can omit this symbols.
I'd use the following reg expression, because the one you wrote finds the files with extension composed of 1 to 3 letters, but usually the extension contains 3 letters(.doc, txt)
Here is the working example:
$string=" some text name.txt some text hello.doc";
preg_match_all("![a-zA-Z0-9_.]+[.][a-zA-Z0-9]{3}!", $string, $w);
print_r($w);
Output:
Array ( [0] => Array ( [0] => name.txt ) )
Related
I have query in my project and that is having REGEXP_REPLACE
i tried to find how it works by searching but i found it like
w+ Matches a word character (that is, an alphanumeric or underscore
(_) character).
but not able to find '"\w+\":' why these "" are used and what is mean by '{|}|"',''
UPDATE (SELECT data,data_value FROM TEMP) t
SET t.DATA_VALUE=REGEXP_REPLACE(REGEXP_REPLACE(t.data, '"\w+\":',''),'{|}|"','');
can you please tell me how it works?
This appear to be a regular expression for stripping keys and enclosing brackets from a JSON string - unfortunately, if this is the case then it does not work in all situations.
The regular expression
'"\w+\":'
will match:
A " double quotation mark;
\w+ one-or-more word (a-z or A-Z or 0-9 or _) characters;
\" another double quotation mark - note: the \ character is not necessary; then
A : colon.
So:
REGEXP_REPLACE(
'{"key":"value","key2":"value with \"quote"}',
'"\w+":', -- Pattern matched
'' -- Replacement string
)
Will output:
{"value","value with \"quote"}
The second pattern {|}|" will match either a {, or a } or a " character (and could have been equivalently written as [{}"]) so:
REGEXP_REPLACE(
'{"value","value with \"quote"}',
'{|}|"', -- Pattern matched
'' -- Replacement string
)
Will output:
value,value with \quote
Which is fine, until (like my example) you have an escaped double quote (or curly braces) in the value string; in which case those will also get stripped leaving the escape character.
(Note: you would not typically find this but it is possible to include escaped quotes in the key. So {"keywith\":quote":"value"} would get replaced to {quote":"value"} and then quote:value which is not the intended output.)
If parsing JSON is what you are trying to do (pre-Oracle 12) then you can use:
REGEXP_REPLACE(
'{"key":"value","key2":"value with \"quote","keywith\":quote":"value with \"{}"}',
'^{|"(\\"|[^"])+":(")?((\\"|[^"])+?)\2((,)|})',
'\3\6'
)
Which outputs:
value,value with \"quote,value with \"{}
Or in Oracle 12 you can do:
SELECT *
FROM JSON_TABLE(
'{"key":"value","key2":"value with \"quote","keywith\":quote":"value with \"{}"}',
'$.*' NULL ON ERROR
COLUMNS (
value VARCHAR2(4000) PATH '$'
)
)
Which outputs:
VALUE
-----------------
value
value with "quote
value with "{}
example:::REGEXP_REPLACE( string, pattern [, replacement_string [, start_position [, nth_appearance [, match_parameter ] ] ] ] )
| is or(CAN MEAN MORE THAN ONE ALTERNATIVE ) , is for at least as in {n,} at least n times
https://www.techonthenet.com/oracle/functions/regexp_replace.php
"where I got my info"
'"\w+\":' why these "" are used and what is mean by '{|}|"',''
Matches a word character(\w)One or more times(+) this has to be messed up it's missing the right quantity of close parentheses by putting \" w+ \"
they allow the " to be shown. This expression takes one expression changes it then uses that as the basis for the next change. Good luck figuring the rest out. Regular expressions aren't too bad, pretty intuitive once you get the basics down.
I have a long text file that reads like:
where the last element of :math:`\pmb{x}_i\in\mathbf{R}^{p}` is 1 and
the first :math:`p-1` elements of :math:`\pmb{x_i}` and
I would like to replace all strings that between :math: and "`" by white spaces. For example, the text above should become:
where the last element of is 1 and
the first elements of and
I tried this:
sed $'/end/ {r exceptions\n} ; /:math:/,/`/ {d}' input_text.text > output_text.text
but this removes the whole line containing the guard strings. I just want to remove what is between the guard strings.
Try this:
sed -E 's/:math:`[^`]*`//g'
Given your input, as output I get
where the last element of is 1 and the first elements of and
It's worth noting that this assumes that the ` character cannot be used inside the :math: tag.
I am trying to perform regular expression matching and replacement on the same line in Ruby. I have some libraries that manipulate strings in Ruby and add special formatting characters to it. The formatting can be applied in any order. However, if I would like to change the string formatting, I want to keep some of the original formatting. I'm using regex for that. I have the regular expression matching correctly what I need:
mystring.gsub(/[(\e\[([1-9]|[1,2,4,5,6,7,8]{2}m))|(\e\[[3,9][0-8]m)]*Text/, 'New Text')
However, what I really want is the matching from the first grouping found in:
(\e\[([1-9]|[1,2,4,5,6,7,8]{2}m))
to be appended to New Text and replaced as opposed to just New Text. I'm trying to reference the match in the form of
mystring.gsub(/[(\e\[([1-9]|[1,2,4,5,6,7,8]{2}m))|(\e\[[3,9][0-8]m)]*Text/, '\1' + 'New Text')
but my understanding is that \1 only works when using \d or \k. Is there any way to reference that specific capturing group in my replacement string? Additionally, since I am using an asterik for the [], I know that this grouping could occur more than once. Therefore, I would like to have the last matching occurrence yielded.
My expected input/output with a sample is:
Input: "\e[1mHello there\e[34m\e[40mText\e[0m\e[0m\e[22m"
Output: "\e[1mHello there\e[40mNew Text\e[0m\e[0m\e[22m"
Input: "\e[1mHello there\e[44m\e[34m\e[40mText\e[0m\e[0m\e[22m"
Output: "\e[1mHello there\e[40mNew Text\e[0m\e[0m\e[22m"
So the last grouping is found and appended.
You can use the following regex with back-reference \\1 in the replacement:
reg = /(\\e\[(?:[0-9]{1,2}|[3,9][0-8])m)+Text/
mystring = "\\e[1mHello there\\e[34m\\e[40mText\\e[0m\\e[0m\\e[22m"
puts mystring.gsub(reg, '\\1New Text')
mystring = "\\e[1mHello there\\e[44m\\e[34m\\e[40mText\\e[0m\\e[0m\\e[22m"
puts mystring.gsub(reg, '\\1New Text')
Output of the IDEONE demo:
\e[1mHello there\e[40mNew Text\e[0m\e[0m\e[22m
\e[1mHello there\e[40mNew Text\e[0m\e[0m\e[22m
Mind that your input has backslash \ that needs escaping in a regular string literal. To match it inside the regex, we use double slash, as we are looking for a literal backslash.
I am trying to write a Ruby regex that will return a set of named matches. If the first element (defined by slashes) is found anywhere later in the string then I want the match to return that 2nd match onward. Otherwise, return the whole string. The closest I've gotten is (?<p1>top_\w+).*?(?<hier>\k<p1>.*) which doesn't work for the 3rd item. I've tried regex ifthen-else constructs but Rubular says it's invalid. I've tried (?<p1>[\w\/]+?)(?<hier>\k<p1>.*) which correct splits the 1st and 4th lines but doesn't work for the others. Please note: I want all results to return as the same named reference so I can iterate through "hier".
Input:
top_cat/mouse/dog/top_cat/mouse/dog/elephant/horse
top_ab12/hat[1]/top_ab12/hat[1]/path0_top_ab12/top_ab12path1/cool
top_bat/car[0]
top_2/top_1/top_3/top_4/top_2/top_1/top_3/top_4/dog
Output:
hier = top_cat/mouse/dog/elephant/horse
hier = top_ab12/hat[1]/path0_top_ab12/top_ab12path1/cool
hier = top_bat/car[0]
hier = top_2/top_1/top_3/top_4/dog
Problem
The reason it does not match the second line is because the second instance of hat does not end with a slash, but the first instance does.
Solution
Specify that there is a slash between the first and second match
Regex
(top_.*)/(\1.*$)|(^.*$)
Replacement
hier = \2\3
Example
Regex101 Permalink
More info on the Alternation token
To explain how the | token works in regex, see the example: abc|def
What this regex means in plain english is:
Match either the regex below (attempting the next alternative only if this one fails)
Match the characters abc literally
Or match the regex below (the entire match attempt fails if this one fails to match)
Match the characters def literally
Example
Regex: alpha|alphabet
If we had a phrase "I know the alphabet", only the word alpha would be matched.
However, if we changed the regex to alphabet|alpha, we would match alphabet.
So you can see, alternation works in a left-to-right fashion.
paths = %w(
top_cat/mouse/dog/top_cat/mouse/dog/elephant/horse
top_ab12/hat/top_ab12/hat[1]/path0_top_ab12/top_ab12path1/cool
top_bat/car[0]
top_2/top_1/top_3/top_4/top_2/top_1/top_3/top_4/dog
test/test
)
paths.each do |path|
md = path.match(/^([^\/]*).*\/(\1(\/.*|$))/)
heir = md ? md[2] : path
puts heir
end
Output:
top_cat/mouse/dog/elephant/horse
top_ab12/hat[1]/path0_top_ab12/top_ab12path1/cool
top_bat/car[0]
top_2/top_1/top_3/top_4/dog
test
Need parse a lot of text files and replace any quoted strings containing cyrillic symbols. They are may contains new lines, non-alphabetic characters and special symbols (for example '$' or escaped quote).
Can anyone help with regex?
From comments:
for example php code
function hello($word) {
$word2 = "ха-ха!";
echo "Привет, $word $word2\n";
}
hello('Мир');
I need match "ха-ха!", "Привет, $word $word2\n" and 'Мир'
This should work:
str = 'The cat is under the "таблица"'
regex = /"\p{Cyrillic}+.*?\.?"/ui
str.match(regex){|s| do_stuff_with_each_matching s}
# or...
str.gsub!(regex){|s| method_that_translates_russian s}
Check it out on live at http://rubular.com/r/0Mwbfinjvp.
http://www.ruby-doc.org/core-1.9.3/Regexp.html
".*[^a-zA-Z\d]+.*" matches any quoted character sequence containing at least one non-alphanumeric character.
i.e. it matches "aa$bb" and "a1$b1"
It doesn't match "aabb" or a$b.
Hope that this is what you want (Add required escaping).