Want to remove / ( -) . from phone number strings - javascript

I want to remove symbols in phone numbers. Sometimes it is in the format of 151-454-6545 but sometimes it is in (545)-(564)-(5465) and in sometimes it is in 548.445.8454. I am using
val.replace(/(\d{3})(\d{3})(\d{4})/, '($1) -$2-$3')
for replacing.. but it doesn't remove the dot.What to do remove the dot also? expected output like 545-455-4545

I suggest to use a non-digit expression to replace them by '-' string :
val.replace(/^\D+/, '')
.replace(/\D+$/, '')
.replace(/\D+/g, '-')
Let me know if it does what you need.
EDIT : trim whitespaces

here is a version with only 1 regex
https://regex101.com/r/Wavw45/1
regex
[^\d\n]*(\d{3})[^\d\n]+(\d{3,4})[^\d\n]+(\d{4})[^\d\n]*
replace (or whatever pattern you want)
($1) -$2-$3

Use
.replace(/^\D*(\d{3})\D*(\d{3})\D*(\d{4})\D*$/, '$1-$2-$3')
See proof.
Explanation
--------------------------------------------------------------------------------
^ the beginning of the string
--------------------------------------------------------------------------------
\D* non-digits (all but 0-9) (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
( group and capture to \1:
--------------------------------------------------------------------------------
\d{3} digits (0-9) (3 times)
--------------------------------------------------------------------------------
) end of \1
--------------------------------------------------------------------------------
\D* non-digits (all but 0-9) (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
( group and capture to \2:
--------------------------------------------------------------------------------
\d{3} digits (0-9) (3 times)
--------------------------------------------------------------------------------
) end of \2
--------------------------------------------------------------------------------
\D* non-digits (all but 0-9) (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
( group and capture to \3:
--------------------------------------------------------------------------------
\d{4} digits (0-9) (4 times)
--------------------------------------------------------------------------------
) end of \3
--------------------------------------------------------------------------------
\D* non-digits (all but 0-9) (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
$ before an optional \n, and the end of the
string

Related

Get headers from markdown using regex

I'm trying to get only h1 and h2 headers from markdown file using regex, but unfortunately I don't know regex well and can't write the correct solution.
With this expression I'm near the solution (I think so):
/\#{1,2} (.*?)(\\r\\n|\\r|\\n)/gm
But it returns also headers with more than two hashes.
Test case:
# first \r
## second \r
### third \r## fourth \r
This should return ['first', 'second', 'fourth']
Use
/(?<!#)#{1,2} (.*?)(\\r(?:\\n)?|\\n)/gm
See regex proof.
EXPLANATION
--------------------------------------------------------------------------------
(?<! look behind to see if there is not:
--------------------------------------------------------------------------------
# '#'
--------------------------------------------------------------------------------
) end of look-behind
--------------------------------------------------------------------------------
#{1,2} '#' (between 1 and 2 times (matching the
most amount possible))
--------------------------------------------------------------------------------
' '
--------------------------------------------------------------------------------
( group and capture to \1:
--------------------------------------------------------------------------------
.*? any character except \n (0 or more times
(matching the least amount possible))
--------------------------------------------------------------------------------
) end of \1
--------------------------------------------------------------------------------
( group and capture to \2:
--------------------------------------------------------------------------------
\\ '\'
--------------------------------------------------------------------------------
r 'r'
--------------------------------------------------------------------------------
(?: group, but do not capture (optional
(matching the most amount possible)):
--------------------------------------------------------------------------------
\\ '\'
--------------------------------------------------------------------------------
n 'n'
--------------------------------------------------------------------------------
)? end of grouping
--------------------------------------------------------------------------------
| OR
--------------------------------------------------------------------------------
\\ '\'
--------------------------------------------------------------------------------
n 'n'
--------------------------------------------------------------------------------
) end of \2

What's the maximum length should I allow to avoid Catastrophic backtracking?

The line is approximately 7915621 in length and is actually the view state value of an ASPX website.
I get the original HTML of the site, then pass it line by line to the extract function, and as soon as it reaches the view_state line containing that long string, the regex become stuck.
Here is the regex pattern that get stuck,
/[\w\.]+\#[\w]+(?:\.[\w]{3}|\.[\w]{2}\.[\w]{2})\b/gi
I thought about setting a maximum line length to skip this line or any other lines like that but I can't think of a optimal size as I care about false positives.
[\w\.]+ is found so many times in your document that it becomes a problem to process them with your expression.
Reducing the amount of places to start searching at is a possible solution. E.g. using a word boundary.
(?:\.\w{3}|\.\w{2}\.\w{2}) can be streamlined as \.\w{2}(?:\w|\.\w{2}).
Use
/\b[\w.]+#\w+\.\w{2}(?:\w|\.\w{2})\b/gi
Or, get rid of the brackets
/\b\w+(?:\.\w+)*#\w+\.\w{2}(?:\w|\.\w{2})\b/gi
EXPLANATION
--------------------------------------------------------------------------------
\b the boundary between a word char (\w) and
something that is not a word char
--------------------------------------------------------------------------------
\w+ word characters (a-z, A-Z, 0-9, _) (1 or
more times (matching the most amount
possible))
--------------------------------------------------------------------------------
(?: group, but do not capture (0 or more times
(matching the most amount possible)):
--------------------------------------------------------------------------------
\. '.'
--------------------------------------------------------------------------------
\w+ word characters (a-z, A-Z, 0-9, _) (1 or
more times (matching the most amount
possible))
--------------------------------------------------------------------------------
)* end of grouping
--------------------------------------------------------------------------------
# '#'
--------------------------------------------------------------------------------
\w+ word characters (a-z, A-Z, 0-9, _) (1 or
more times (matching the most amount
possible))
--------------------------------------------------------------------------------
\. '.'
--------------------------------------------------------------------------------
\w{2} word characters (a-z, A-Z, 0-9, _) (2
times)
--------------------------------------------------------------------------------
(?: group, but do not capture:
--------------------------------------------------------------------------------
\w word characters (a-z, A-Z, 0-9, _)
--------------------------------------------------------------------------------
| OR
--------------------------------------------------------------------------------
\. '.'
--------------------------------------------------------------------------------
\w{2} word characters (a-z, A-Z, 0-9, _) (2
times)
--------------------------------------------------------------------------------
) end of grouping
--------------------------------------------------------------------------------
\b the boundary between a word char (\w) and
something that is not a word char

I want to limit number of subdomain in Regular Expression

I want to limit levels of subdomain to 3 levels only. trying regex below fails
([\.]?[a-z]*){3}
My Target: abc.def.ghi
but
regex above accepts abc.def.ghi. (Notice the last .)
Use
^(?:[a-z]+(?:\.[a-z]+){0,2})?$
See proof.
Explanation
--------------------------------------------------------------------------------
^ the beginning of the string
--------------------------------------------------------------------------------
(?: group, but do not capture (optional
(matching the most amount possible)):
--------------------------------------------------------------------------------
[a-z]+ any character of: 'a' to 'z' (1 or more
times (matching the most amount
possible))
--------------------------------------------------------------------------------
(?: group, but do not capture (between 0 and
2 times (matching the most amount
possible)):
--------------------------------------------------------------------------------
\. '.'
--------------------------------------------------------------------------------
[a-z]+ any character of: 'a' to 'z' (1 or
more times (matching the most amount
possible))
--------------------------------------------------------------------------------
){0,2} end of grouping
--------------------------------------------------------------------------------
)? end of grouping
--------------------------------------------------------------------------------
$ before an optional \n, and the end of the
string

Javascript regex for specific name validation

I have a university assignment to write a JS regex for name validation: name can include spaces at the beginning and the end (don't ask anything, it's our teacher demand), also it can include such chars like: -, ' and space (" "). At the moment, my regex looks like that:
var Nameregex = /^( ?)*[A-Z]+((['-])?[a-z]+)*(([ ]?[a-z]*)*)*$/g;
It works almost perfect, but except for one case: one word (words separated from each other with spaces and - symbols) can contain only one ' symbol.
For example, names like John-andrew'andrew'john shouldn't work. But John-andrew'john-andrew'john should work.
Add a (?!.*'[A-Za-z]+') negative lookahead after ^:
/^(?!.*'[A-Za-z]+')\s*[A-Z]+(?:['-]?[a-z]+)*(?:\s*[a-z]*)*$/
See proof
Explanation
--------------------------------------------------------------------------------
^ the beginning of the string
--------------------------------------------------------------------------------
(?! look ahead to see if there is not:
--------------------------------------------------------------------------------
.* any character except \n (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
' '\''
--------------------------------------------------------------------------------
[A-Za-z]+ any character of: 'A' to 'Z', 'a' to 'z'
(1 or more times (matching the most
amount possible))
--------------------------------------------------------------------------------
' '\''
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
\s* whitespace (\n, \r, \t, \f, and " ") (0 or
more times (matching the most amount
possible))
--------------------------------------------------------------------------------
[A-Z]+ any character of: 'A' to 'Z' (1 or more
times (matching the most amount possible))
--------------------------------------------------------------------------------
(?: group, but do not capture (0 or more times
(matching the most amount possible)):
--------------------------------------------------------------------------------
['-]? any character of: ''', '-' (optional
(matching the most amount possible))
--------------------------------------------------------------------------------
[a-z]+ any character of: 'a' to 'z' (1 or more
times (matching the most amount
possible))
--------------------------------------------------------------------------------
)* end of grouping
--------------------------------------------------------------------------------
(?: group, but do not capture (0 or more times
(matching the most amount possible)):
--------------------------------------------------------------------------------
\s* whitespace (\n, \r, \t, \f, and " ") (0
or more times (matching the most amount
possible))
--------------------------------------------------------------------------------
[a-z]* any character of: 'a' to 'z' (0 or more
times (matching the most amount
possible))
--------------------------------------------------------------------------------
)* end of grouping
--------------------------------------------------------------------------------
$ before an optional \n, and the end of the
string

Javascript Regex Input Validation to Prevent Duplicate Characters

I am attempting to validate text input with the following requirements:
allowed characters & length /^\w{8,15}$/
must contain /[a-z]+/
must contain /[A-Z]+/
must contain /[0-9]+/
must not contain repeated characters (ie. aba=pass and aab=fail)
Each test would return true when used with .test().
With modest familiarity, I am able to write the first 4 tests, albeit individually. The 5th test is not working out, negated lookahead (which is what i believe i need to be using) is challenging.
Here are a few value/result examples:
re.test("Fail1");//returns false, too short
re.test("StringFailsRule1");//returns false, too long
re.test("Fail!");//returns false, invalid !
re.test("FAILRULE2");//returns false, missing [a-z]+
re.test("failrule3");//returns false, missing [A-Z]+
re.test("failRuleFour");//returns false, missing [0-9]+
re.test("failRule55");//returns false, repeat of "5"
re.test("TestValue1");//returns true
Finally, the ideal would be a single combined test used to enforce all requirements.
This uses negative and positive lookaheads zero-length assertions for your tests and the .{8,15} bit validates length.
^(?!.*(.)\1)(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])\w{8,15}$
For your fifth rule I used a negative lookahead to make sure that a capture group of any character is never followed by itself.
Regexpal demo
NODE EXPLANATION
--------------------------------------------------------------------------------
^ the beginning of the string
--------------------------------------------------------------------------------
(?! look ahead to see if there is not:
--------------------------------------------------------------------------------
.* any character except \n (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
( group and capture to \1:
--------------------------------------------------------------------------------
. any character except \n
--------------------------------------------------------------------------------
) end of \1
--------------------------------------------------------------------------------
\1 what was matched by capture \1
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
(?= look ahead to see if there is:
--------------------------------------------------------------------------------
.* any character except \n (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
[a-z] any character of: 'a' to 'z'
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
(?= look ahead to see if there is:
--------------------------------------------------------------------------------
.* any character except \n (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
[A-Z] any character of: 'A' to 'Z'
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
(?= look ahead to see if there is:
--------------------------------------------------------------------------------
.* any character except \n (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
[0-9] any character of: '0' to '9'
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
\w{8,15} word characters (a-z, A-Z, 0-9, _)
(between 8 and 15 times (matching the most
amount possible))
--------------------------------------------------------------------------------
$ before an optional \n, and the end of the
string

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