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I need a regular expression for a string that
starts with Alphabets (no number)
max Length 8
No special characters or space.
string can have number or _ except for starting character.
This would work:
/^[a-z][a-z0-9_]{0,7}$/i
For example,
/^[a-z][a-z0-9_]{0,7}$/i.test('a1234567'); // true
/^[a-z][a-z0-9_]{0,7}$/i.test('01234567'); // false
The \w shorthand is for all letters, numbers and underscores. [A-Za-z] is overkill, the /i flag will get you all letters, case insensitive.
Therefore, a super simple regex for what you need is:
/^[a-z]\w{0,7}$/i
/^[a-z]\w{0,7}$/i.test("a1234567");
> true
/^[a-z]\w{0,7}$/i.test("a12345697");
> false
/^[a-z]\w{0,7}$/i.test("01234567");
> false
Try this out:
/^[A-Za-z]{1}[a-zA-Z0-9_]{0,7}$/
Try this one:
/^[a-zA-Z][0-9a-zA-Z_]{0,7}$/
This requires an alpha start character, and optionally allows up to 7 more characters which are either alphanumeric or underscore.
EDIT: Thanks, Jesse for the correction.
And another version with lookaheads :)
if (subject.match(/^(?=[a-z]\w{0,7}$)/i)) {
// Successful match
}
Explanation :
"^" + // Assert position at the beginning of the string
"(?=" + // Assert that the regex below can be matched, starting at this position (positive lookahead)
"[a-z]" + // Match a single character in the range between “a” and “z”
"\\w" + // Match a single character that is a “word character” (letters, digits, etc.)
"{0,7}" + // Between zero and 7 times, as many times as possible, giving back as needed (greedy)
"$" + // Assert position at the end of the string (or before the line break at the end of the string, if any)
")"
Related
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I want a regular expression which validates my input e.g "S19/999999/090". my input field should accept this kind of input. means the first character should be an uppercase alphabet from A-Z after that two digits from 0-9. after that one backslash. after that 6 digits from 0-9 after that one backslash. after that 3 digits from 0-9.
E.g "S19/999999/090"
I don't understand how to create this kind of regular expression.
Thank you in advance
check the attached fiddle. [https://regex101.com/r/IQsyv2/1/]
and regex will be like -
^[A-Z][\d]{2}/[\d]{6}/[\d]{3}$
here initially to notice I have specified ^ and $ these char are used to define the full length match, mean ^ - says starting and $ says ending.
[A-Z] - mean check uppercase only once.
[\d]{2} - mean [\d] any digit, {2} - 2 times
\/ -- mean match backslash
[\d]{6} - only digit 6 times exactly.
\/ -- mean match backslash
[\d]{3} - only digit 3 times exactly.
Try this
[A-Z]\d{2}\/\d{6}\/\d{3}
[A-Z] - one character A-Z uppercase
\d - digital
\d{n} - n digital
/\ - /
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I need to create an expression that fit this requirements :
The string must be composed by 3 substring
The first substring accept 0-9a-zA-Z, the minimum length is 1 and there is notte max length
The second substring must be " - "
The last have The first's one same condition
Total maximum string length must be 28 chars
It is possible to accomplish this requirement with Regex?
Following regex should work fine:
/(?=^.{3,28}$)[^\W_]+\-[^\W_]+/
var array = [
"123456790-123456789012345678",
"123456790-1234567890123456789",
"adsd-dsds"
];
var re = /(?=^.{3,28}$)[^\W_]+\-[^\W_]+/;
array.forEach(e => console.log(re.test(e) ? e.match(re)[0]: "match failed"));
Breakdown shamelessly copied from regex101.com:
Positive Lookahead (?=^.{3,28}$)
^ asserts position at start of a line
.{3,28} matches any character (except for line terminators)
{3,28} Quantifier — Matches between 3 and 28 times, as many times as possible, giving back as needed (greedy)
$ asserts position at the end of a line
Match a single character not present in the list below [^\W_]+
+ Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)
\W matches any non-word character (equal to [^a-zA-Z0-9_])
_ matches the character _ literally (case sensitive)
\- matches the character - literally (case sensitive)
Match a single character not present in the list below [^\W_]+
+ Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)
\W matches any non-word character (equal to [^a-zA-Z0-9_])
_ matches the character _ literally (case sensitive)
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I have two words within sentence.
EX: big BUTTON
here I need to check second word is in uppercase using regex expression.
Square brackets [] are your friend. They allow you to specify characters that will match. To match the first work, you need to check for any letter. This can be done with [a-zA-Z]. This will match any letter between a and z, as well as A and Z. for the second word, you only want to match uppercase, so only use [A-Z]. To get 1 or more matches, put a + after the closing bracket.
Putting this all together, with a space in between the words, you get [a-zA-Z]+ [A-Z]+.
The carat ^ is used to signify the start of the string, and the dollar sign $ is used to signify the end of the string. Your question somewhat vague, so here are a couple scenarios:
Each sentence is only two words with a space in between them: ^[a-zA-Z]+ [A-Z]+$
Each sentence has at least two words and may or may not end in a period: ^[a-zA-Z]+ [A-Z]+( |\.?$)
In the second example the parenthesis with a pipe (|) is used as an OR statement. The period is escaped since it is a special character (matches any single character). The question mark denotes 0 or 1 of the preceding character, which is a period. So ( |\.?$) will match a space or a sentence that ends with or without a period.
Here is a good site that has information on Regexes: http://www.regular-expressions.info/
This regexp looks for any sequence, starting at the beginning of the string (^), of alphanumeric characters (\w)--that's the first word--then a space, followed by a sequence of upper-case letters ([A-Z]+)--the second word--followed by either a space or the end of the string ($).
/^\w+ [A-Z]+( |$)/
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I have textbox and I want get string value. But I want users to not be able to enter the string that has number on first letter. As matter of fact I want to replace number with '' null.
for example
1test =====convert=======> test
you can simply use ^[a-zA-Z]
^ starts with a-z or A-Z
or if you want special character too then use ^\D
^\D : Matches anything other than a decimal digit
Regex Demo
you can use $text.replace(/^[^0-9]+/, '')
/^ beginning of the line
[^0-9]+ match anything other than digits at-least once
thanks # Wiktor and Tushar
here is the solution: You can check on this live regex.
https://regex101.com/r/OJfyv4/1
$re = '/\b[a-z][a-z0-9]*/';
$str = '1test';
preg_match_all($re, $str, $matches);
// Print the entire match result
print_r($matches);
This works your case:
^\d+
https://regex101.com/r/daezA9/1
^ asserts position at start of the string
\d matches a digit (equal to [0-9])
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How in javascript to make regex to recognize and extract integer numbers for coordinates which have format like
( number1, number2 )
between ( and number1 and , and number2 and ) can be arbitrary number of whitespaces (user are going to enter coordinates so I don't want to force strict format without whitespaces)
(\d+,\d+)
what to add to this so it works ?
There are a few choices, pending your actual input.
To match all "whitespace characters" (space, tab, carriage return, newline and form feed), you can use the \s shorthand approach. If you want a number, in this case \d+, to be surrounded by "0 or more" of these, you would use:
\s*\d+\s*
In your full pattern:
\( # opening parentheses
\s*\d+\s*, # first number followed by a comma
\s*\d+\s* # second number
\) # closing parentheses
Note: The parentheses are escaped here as they're special characters in a regular expression pattern.
Now, if you don't want to match "all whitespace" and were only interested in plain spaces, for example, you could use a matching character set of [ ] (i.e. a space between two brackets). In the pattern from above:
\(
[ ]*\d+[ ]*,
[ ]*\d+[ ]*
\)
Not really sure how you want to use the matches, I'm assuming you want the numbers returned individually so in that case, you can use the following:
var str = '(1, 2)';
var matches = str.match(/\(\s*(\d+)\s*,\s*(\d+)\s*\)/);
if (matches) {
var firstNumber = matches[1];
var secondNumber = matches[2];
// do stuffs
}
Note: In the pattern I used here, I've wrapped the \d+s in parentheses; this will "capture" those values in to groups which are then accessible by their "group index". So, the first (\d+) will be available in matches[1] and the second will be available in matches[2].
Try this regex: \(\s*\d+\s*,\s*\d+\s*\).
Fiddle