In a web application, while validating the textbox using a regular expression, I have written the expression to validate only digits not starting with zero, with 3 digits after the decimal points. But if I type only a single digit, it's giving me a message. Can you help me with the regular expression? I'm looking for an expression which would not accept a leading digit of zero and accept only 3 decimals like 12.336, 1.254, 10.20, etc.
Depending on exactly what you want:
This will match numbers not begining with 0 and having exactly 3 decimal
^[1-9]\d*\.\d{3}$
This will match numbers not begining with 0 and having 1 to 3 decimal or none.
^[1-9]\d*(?:\.\d{1,3})?$
This should do the trick:
[1-9]\d*\.?\d{0,3}
If you wish to ignore whitespace, just add \s*:
\s*[1-9]\d*\.?\d{0,3}\s*
BTW, there are ton of visual tools for writing regular expressions – I recommend Expresso.
This is what you want:
^[1-9]\d*.?\d{0,3}$
Note this will also fail if there are spaces at either end of the string, remove the ^ at the start and the $ at the end if this is not as desired.
Related
This may be a very simple question but I have not much experience with regex expressions. This page is a good source of regex expressions but could not figure out how to include them into my following code:
data %>% filter(grepl("^A01H1", icl))
Question
I would like to extract the values in one column of my data frame starting with this A01H1 up to 2 more digits, for example A01H100, A01H140, A01H110. I could not find a solution despite my few attempts:
Attempts
I looked at this question from which I used ^A01H1[0-9].{2} to select up tot two more digits.
I tried with adding any character ^A01H1[0-9][0-9][x-y] to stop after two digits.
Any help would be much appreciated :)
You can use "^A01H1\\d{1,2}$".
The first part ("^A01H1"), you figured out yourself, so what are we doing in the second part ("\\d{1,2}$")?
\d includes all digits and is equivalent to [0-9], since we are working in R you need to escape \ and thus we use \\d
{1,2} indicates we want to have 1 or 2 matches of \\d
$ specifies the end of the string, so nothing should come afterwards and this prevents to match more than 2 digits
It looks as if you want to match a part of a string that starts with A01H1, then contains 1 or 2 digits and then is not followed with any digit.
You may use
^A01H1\d{1,2}(?!\d)
See the regex demo. If there can be no text after two digits at all, replace (?!\d) with $.
Details
^ - start of strinmg
A01H1 - literal string
\d{1,2} - one to two digits
(?!\d) - no digit allowed immediately to the right
$ - end of string
In R, you could use it like
grepl("^A01H1\\d{1,2}(?!\\d)", icl, perl=TRUE)
Or, with the string end anchor,
grepl("^A01H1\\d{1,2}$", icl)
Note the perl=TRUE is only necessary when using PCRE specific syntax like (?!\d), a negative lookahead.
I need to use an asp:RegularExpressionValidator control in my asp.net site and I want to restrict the characters to digits and semi-colon only.
So it needs to be able to take any amount of digits and ;
Valid values:
123
123;456
123;456;789;....
What is the regex for that?
Try this simple regex: [0-9;]+ or [\d;]+
\d match a digit [0-9]
; the literal character ;
+ means that it match between one character and unlimited times, as many times as possible,
If you want to guarantee that at least numbers are present in your expression you could do this too:
#npinti has a valid point better will be: ^[\d;]+$
where ^ indicates the begging of your expression and $ the end of it.
Online Demo
What is the regex that matches these examples(6 characters, first is a letter, others are numbers):
u78945 - valid
s56123 - valid
456a12 - invalid
78561d - invalid
1234567 - invalid
i don't know if regular expressions are the same for every programming language. I need it for Regular Expression Validator control using VB ASP.NET.
Use this pattern:
^[a-z][0-9]{5}$
This will match any Latin letter (lower-case unless using case-insensitive matching) followed by 5 decimal digits.
Note: You could use \d instead of [0-9], but read this for an explanation about why they are different.
[a-zA-Z]\d{5}
If you are searching explicitly from the beginning of the line use ^
^[a-zA-Z]\d{5}
and append $ for the end of the line.
^[a(?i)-z(?i)]\d{5}$
The (?i) code enables the expression to accept any letter without case-sensitivity. The \d{5} looks for a sequence of numbers whose length is exactly 5.
I have some textboxes I'm using as search-fields.
The textbox can be empty, but when a search-criteria is filled in, it must be at least 3 characters long, ignoring the spaces in the count.
I've found that a regularexpressionvalidator validates true when the textbox is empty, so that part is ok.
Q: regex for a minimumlenth of 3 characters. Spaces are allowed, but should not count in the length.
Thanks.
Have you tried something like this?
'(\s*\w\s*){3}'
This regular expression looks for a character (\w) optionally surronded by any whitespace (\s*) three times ({3}), which is what you're looking for.
Note: I don't know asp.net, but I think the regular expression is all you need to solve the problem.
I'm having a hard time trying to create a right regular expression for the RegularExpressionValidator control that allows password to be checked for the following:
- Is greater than seven characters.
- Contains at least one digit.
- Contains at least one special (non-alphanumeric) character.
Cant seem to find any results out there too. Any help would be appreciated! Thanks!
Maybe you will find this article helpful. You may try the following expression
^.*(?=.{8,})(?=.*[\d])(?=.*[\W]).*$
and the breakdown:
(?=.{8,}) - contains at least 8 characters
(?=.*[\d]) - contains at least one digit
(?=.*[\W]) - contains at least one special character
http://msdn.microsoft.com/en-us/library/ms972966.aspx
Search for "Lookaround processing" which is necessary in these examples. You can also test for a range of values by using .{4,8} as in Microsoft's example:
^(?=.*\d).{4,8}$
Try this
((?=.*\d)(?=.*[a-z])(?=.*[\W]).{6,20})
Description of above Regular Expression:
( # Start of group
(?=.*\d) # must contains one digit from 0-9
(?=.*[a-z]) # must contains one lowercase characters
(?=.*[\W]) # must contains at least one special character
. # match anything with previous condition checking
{7,20} # length at least 7 characters and maximum of 20
) # End of group
"/W" will increase the range of characters that can be used for password and pit can be more safe.
Use for Strong password with Uppercase, Lowercase, Numbers, Symbols & At least 8 Characters.
//Code for Validation with regular expression in ASP.Net core.
[RegularExpression(#"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[^\da-zA-Z]).{8,15}$")]
Regular expression password validation:
#"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[^\da-zA-Z]).{8,15}$"