So if we have some txt file with variable line length, how to search with emacs regex lines with fewer of some number (let say 20) of characters.
This should do the job it matches any line with between 0 and 20 tokens on it
^[^\n]{0,20}$
^ Start of a line (or String)
[^\n] Anything that is not a new line
{0,20} The previous between 0 and 20 times
$ End of line (or String)
Related
There is the following regular expression:
^[1-9]\d{0,8}[\r\n]?$
It describes one line of text.
How to indicate that this expression is applicable to 1 or more lines of text? I do not exclude that changes will be required in the above expression.
ou have a ^[line_pattern]$ regex. To expand it to validate a multiline string where each line shouldmeet the same [line_pattern] use ^[line_pattern](?:\r?\n[line_pattern])*$. In some engines that support the \R line break regex construct, replace \r?\n with it.
You may use
^[1-9]\d{0,8}(?:\r?\n[1-9]\d{0,8})*$
or
^[1-9]\d{0,8}(?:\R[1-9]\d{0,8})*$
It matches
^ - start of a string
[1-9]\d{0,8} - a non-zero digit followed with 0 to 8 any digits
(?:\r?\n[1-9]\d{0,8})* - 0 or more repetitions of
\r?\n - a CRLF or an LF only line ending (\R matches any line break sequence)
[1-9]\d{0,8} - a non-zero digit followed with 0 to 8 any digits
$ - end of string.
Your expression was for a single line. I have simply changed your expression to say there will be one or more of them using parentheses and a plus to indicate 'one or more'.
I have also edited the way you defend the end of the line. I am assuming that there is always a CRLF or LF at the end of each number:
^([1-9]\d{0,8}\r?\n)+$
I have a text file where almost all the lines start with the letter N followed by 3 or 4 numbers as below
N970 G2 X-1.0591 Y-1.7454 I0. J-.04
N980 G1 Y-1.7554
N990 X-1.0594 Y-1.7666
N1000 Z-.2187
N1010 Y-1.7566
How can I remove the N followed by the 3 or 4 numbers in Notepad++ to look like this? if i need to search twice (once for N### and then again for N####) that is fine also.
G2 X-1.0591 Y-1.7454 I0. J-.04
G1 Y-1.7554
X-1.0594 Y-1.7666
Z-.2187
Y-1.7566
the numbers go from 100-9990 in increments of 10 if that helps
You can use the following regex that should work for your case:
^N[0-9]+\s*(.*)
It will match every line that starts with a capital letter N immediately followed by one or more digits. Matched results will include a single group which will contain the text you are looking for.
Note that whitespaces between the N tags and the actual text will not be matched.
Try it out in this DEMO
Breakdown
^ # Assert position at the start of the line
N # Matches capital letter 'N' literally
[0-9]+ # Matches any digit between 1 and unlimited times
\s* # Matches whitespace between 0 and unlimited times
(.*) # The rest of the text you are looking for
Find/Replace
The regex will match each individual line so you can either select Find Next and then Replace and process your file one line at a time or you can choose Replace All to process the whole file at once.
Substitution line (Replace with:) line should just include the first group ($1) which represents the rest of your text with N-prefix tags trimmed.
Make sure that the Search Mode is set to Regular expression.
I have a file containing many lines of the following
line 123456 89 2018-02-12 14:47:07 +0000 here
line 234567 90 2019-02-13 09:02:01 +0000 there
So I would like to split them into the last four parts from each line
Here is the regular expresion that
"\t\d{6}\t\d{2}\t\w+"
It gives out
123456\t89\t2018
234567\t90\t2019
How do I update the regular expression to get
123456\t89\t2018-02-12 14:47:07\there
234567\t90\t2019-02-13 09:02:01\tthere
instead?
Thanks!
The end of your regex "\t\d{6}\t\d{2}\t\w+" matches up to the next non-word character, which happens to be the dash after the year item. To capture the remaining characters, I'd recommend a negative character class, which matches everything except \t. That is:
"\t\d{6}\t\d{2}\t[^\t]+\t\w+"
Usually, this is easier than positively stating all possible characters that might occur.
I want to find all lines in a file containing a number, but not at the beginning of a line. I tried the following:
grep -E '[^^][1-9]?[0-9]+' test.txt
However, it does not work: this expression matches the lines starting with numbers consisting of two-(or more) digits. As I understand it, [^^] does not mean "any symbol except the beginning of a line". Why is so, and how to write this correctly?
Edited according to comment:
This Regex should do it, it matches lines not starting with a number (one or more characters), then find one or more numbers.
^[^1-9]+?\d+
You will need to set the 'multiline' option, if you check multiple lines at one time.
Your issue is the [^^] part of your regex. That is a negative character class (a ^ inside the [ ] negates what is inside the brackets).
Instead, I think you are looking for ^ outside of the brackets to state 'start of the line' and then a negated character class of [^0-9] for something other than a digit at the start of the line:
$ echo "1 line
line 2
3 line
line 4
no num" | grep '^[^0-9]'
line 2
line 4
no num
Then add .* for 'anything of any length' and [0-9] for at least one digit to filter for lines that have a digit in the line:
$ echo "1 line
line 2
3 line
line 4
no num" | grep '^[^0-9].*[0-9]'
line 2
line 4
Or, if you want to be locale aware, you can use POSIX character classes to the same result:
$ echo "1 line
line 2
3 line
line 4
no num" | grep '^[^[:digit:]].*[[:digit:]]'
line 2
line 4
I want to validate my input records coming one by one from file. And my file can contain 10,000 to 20,000 records
Record can have only (capital aplphabets, -, dot, spaces and numbers) only. And record ends up with new line character. It could be one of them (\n or \r\n)
I want regex to match record only having above five parameters with including new character of both type (\n or \r\n). If record contains other character from I've mentioned should not be matched.
I've tried this regex.
[A-Z\d\- ]{120}\s+$
lets take an example for 10 characters.
1) Input
AAAA12.0 A\nor\r\n
Regex should match for given input(1) because of exact ten characters plus new line character(one is possible at a time)
2)Input
AA-A13.0 AAA\nor\r\n
Regex should match for given input(2) because number of characters are more than 10
But this regex fails sometime. Any suggestion on this regex to improve and make it more strict on my five requirements ?
This expression:
^[-.A-Z \d]*\r?$
Matches if the entire line consists of only hyphen, dot, capital A-Z, space, and digit, and ends with \n or optionally \r\n.