Regular Expression to avoid negative values - regex

I am totally new to creating my own regular expressions. I have one reg ex developed my team member as listed below
^\s*-?\d{1,3}(\.\d{1,4})?\s*$
This will ensure that the value entered is having a maximum of 3 digits and may or may not have a negative sign.
RegExp Calculator
If I test with a value, “-1000” it will say the entered value does not meet the requirements and an error will be shown to the user.
I need to modify the expression in such way that:
If a “-“ sign is there, it can have more than 3 digits and decimals. [But if the user enter a “-“ and any alphabets, it should not match ]

You could change it to this one :
^\s*(\d{1,3}|-\d+)(\.\d{1,4})?\s*$
The first part in the form (a|b) means a or b. It means that the part before the comma is either
1 to 3 digits
or - followed by at least one digit

Use |(OR) operator in regex
^(\d{1,3}([.]\d{1,4})?|-\d+([.]\d+)?)$

If you just want to validate if a number is between -999 and 999 please parse it to an Integer and check -999 < x < 999.

Related

regular expression that accepts numbers like 1,000.10? [duplicate]

I need regex to validate a number that could contain thousand separators or decimals using javascript.
Max value being 9,999,999.99
Min value 0.01
Other valid values:
11,111
11.1
1,111.11
INVALID values:
1111
1111,11
,111
111,
I've searched all over with no joy.
/^\d{1,3}(,\d{3})*(\.\d+)?$/
About the minimum and maximum values... Well, I wouldn't do it with a regex, but you can add lookaheads at the beginning:
/^(?!0+\.00)(?=.{1,9}(\.|$))\d{1,3}(,\d{3})*(\.\d+)?$/
Note: this allows 0,999.00, so you may want to change it to:
/^(?!0+\.00)(?=.{1,9}(\.|$))(?!0(?!\.))\d{1,3}(,\d{3})*(\.\d+)?$/
which would not allow a leading 0.
Edit:
Tests: http://jsfiddle.net/pKsYq/2/
((\d){1,3})+([,][\d]{3})*([.](\d)*)?
It worked on a few, but I'm still learning regex as well.
The logic should be 1-3 digits 0-1 times, 1 comma followed by 3 digits any number of times, and a single . followed by any number of digits 0-1 times
First, I want to point out that if you own the form the data is coming from, the best way to restrict the input is to use the proper form elements (aka, number field)
<input type="number" name="size" min="0.01" max="9,999,999.99" step="0.01">
Whether "," can be entered will be based on the browser, but the browser will always give you the value as an actual number. (Remember that all form data must be validated/sanitized server side as well. Never trust the client)
Second, I'd like to expand on the other answers to a more robust (platform independent)/modifiable regex.
You should surround the regex with ^ and $ to make sure you are matching against the whole number, not just a subset of it. ex ^<my_regex>$
The right side of the decimal is optional, so we can put it in an optional group (<regex>)?
Matching a literal period and than any chain of numbers is simply \.\d+
If you want to insist the last number after the decimal isn't a 0, you can use [1-9] for "a non-zero number" so \.\d+[1-9]
For the left side of the decimal, the leading number will be non-zero, or the number is zero. So ([1-9]<rest-of-number-regex>|0)
The first group of numbers will be 1-3 digits so [1-9]\d{0,2}
After that, we have to add digits in 3s so (,\d{3})*
Remember ? means optional, so to make the , optional is just (,?\d{3})*
Putting it all together
^([1-9]\d{0,2}(,?\d{3})*|0)(\.\d+[1-9])?$
Tezra's formula fails for '1.' or '1.0'. For my purposes, I allow leading and trailing zeros, as well as a leading + or - sign, like so:
^[-+]?((\d{1,3}(,\d{3})*)|(\d*))(\.|\.\d*)?$
In a recent project we needed to alter this version in order to meet international requirements.
This is what we used: ^-?(\d{1,3}(?<tt>\.|\,| ))((\d{3}\k<tt>)*(\d{3}(?!\k<tt>)[\.|\,]))?\d*$
Creating a named group (?<tt>\.|\,| ) allowed us to use the negative look ahead (?!\k<tt>)[\.|\,]) later to ensure the thousands separator and the decimal point are in fact different.
I have used below regrex for following retrictions -
^(?!0|\.00)[0-9]+(,\d{3})*(.[0-9]{0,2})$
Not allow 0 and .00.
','(thousand seperator) after 3 digits.
'.' (decimal upto 2 decimal places).

Regular expression Range with decimal validation

I am trying to set the minimal amount that can be donated on a donation form to be $5.00. The field property allows me to validate using a regular expression. The problem with my expression is that it allows users to donate amounts less than $5.00 if they use decimals. eg $1.99 or $2.50 or $3.75. I need help coming up with a regular expression that will restrict users from using decimal points. Any help will be greatly appreciated.
Thanks
Here is what I have ...
/([5-9]|[1-8][0-9]|9[0-9]|[1-8][0-9]{2}|9[0-8][0-9]|99[0-9]|[1-8][0-9]{3}|9[0-8][0-9]{2}|99[0-8][0-9]|999[0-9]|[1-8][0-9]{4}|9[0-8][0-9]{3}|99[0-8][0-9]{2}|999[0-8][0-9]|9999[0-9]|[1-8][0-9]{5}|9[0-8][0-9]{4}|99[0-8][0-9]{3}|999[0-8][0-9]{2}|9999[0-8][0-9]|99999[0-9]|[1-8][0-9]{6}|9[0-8][0-9]{5}|99[0-8][0-9]{4}|999[0-8][0-9]{3}|9999[0-8][0-9]{2}|99999[0-8][0-9]|999999[0-9]|10000000)/
Here you go:
^0*([5-9]|[1-9]\d{1,})(\.\d{1,2})?$
Test link : https://regex101.com/r/p65pXd/4
Explanation:
^0* means any number of leading zeros
[5-9] is a single number between 5 to 9 (both included)
[1-9]\d{1,} is a number greater or equal to 10
Then we put both of the previous regexs into ( | ) to have a 'OR' condition to match one of those
Then we can add (\.\d{1,2})?, means "optionally followed by a dot and 1 or 2 numbers."
We can surround this ^ and $ meaning beginning and end of input.

Optimization of Regular Expression to match numbers bigger or equal to 50

I want to check if a number is 50 or more using a regular expression. This in itself is no problem but the number field has another regex checking the format of the entered number.
The number will be in the continental format: 123.456,78 (a dot between groups of three digits and always a comma with 2 digits at the end)
Examples:
100.000,00
50.000,00
50,00
34,34
etc.
I want to capture numbers which are 50 or more. So from the four examples above the first three should be matched.
I've come up with this rather complicated one and am wondering if there is an easier way to do this.
^(\d{1,3}[.]|[5-9][0-9]|\d{3}|[.]\d{1,3})*[,]\d{2}$
EDIT
I want to match continental numbers here. The numbers have this format due to internal regulations and specify a price.
Example: 1000 EUR would be written as 1.000,00 EUR
50000 as 50.000,00 and so on.
It's a matter of taste, obviously, but using a negative lookahead gives a simple solution.
^(?!([1-4]?\d),)[1-9](\d{1,2})?(\.\d{3})*,\d{2}\b
In words: starting from a boundary ignore all numbers that start with 1 digit OR 2 digits (the first being a 1,2,3 or 4), followed by a comma.
Check on regex101.com
Try:
EDIT ^(.{3,}|[5-9]\d),\d{2}$
It checks if:
there 3 chars or more before the ,
there are 2 numbers before the , and the first is between 5 and 9
and then a , and 2 numbers
Donno if it answer your question as it'll return true for:
aa50,00
1sdf,54
But this assumes that your original string is a number in the format you expect (as it was not a requirement in your question).
EDIT 3
The regex below tests if the number is valid referring to the continental format and if it's equal or greater than 50. See tests here.
Regex: ^((([1-9]\d{0,2}\.)(\d{3}\.){0,}\d{3})|([1-9]\d{2})|([5-9]\d)),\d{2}$
Explanation (d is a number):
([1-9]\d{0,2}\.): either d., dd. or ddd. one time with the first d between 1 and 9.
(\d{3}\.){0,}: ddd. zero or x time
\d{3}: ddd 3 digit
These 3 parts combined match any numbers equals or greater than 1000 like: 1.000, 22.002 or 100.000.000.
([1-9]\d{2}): any number between 100 and 999.
([5-9]\d)): a number between 5 and 9 followed by a number. Matches anything between 50 and 99.
So it's either the one of the parts above or this one.
Then ,\d{2}$ matches the comma and the two last digits.
I have named all inner groups, for better understanding what part of number is matched by each group. After you understand how it works, change all ?P<..> to ?:.
This one is for any dec number in the continental format.
^(?P<common_int>(?P<int>(?P<int_start>[1-9]\d{1,2}|[1-9]\d|[1-9])(?P<int_end>\.\d{3})*|0)(?!,)|(?P<dec_int_having_frac>(?P<dec_int>(?P<dec_int_start>[1-9]\d{1,2}|[1-9]\d|[1-9])(?P<dec_int_end>\.\d{3})*,)|0,|,)(?=\d))(?P<frac_from_comma>(?<=,)(?P<frac>(?P<frac_start>\d{3}\.)*(?P<frac_end>\d{1,3})))?$
test
This one is for the same with the limit number>=50
^(?P<common_int>(?P<int>(?P<int_start>[1-9]\d{1,2}|[1-9]\d|[1-9])(?P<int_end>\.\d{3})+|(?P<int_short>[1-9]\d{2}|[5-9]\d))(?!,)|(?P<dec_int_having_frac>(?P<dec_int>(?P<dec_int_start>[1-9]\d{1,2}|[1-9]\d|[1-9])(?P<dec_int_end>\.\d{3})+,)|(?P<dec_short_int>[1-9]\d{2}|[5-9]\d),)(?=\d))(?P<frac_from_comma>(?<=,)(?P<frac>(?P<frac_start>\d{3}\.)*(?P<frac_end>\d{1,3})))?$
tests
If you always have the integer part under 999.999 and fractal part always 2 digits, it will be a bit more simple:
^(?P<dec_int_having_frac>(?P<dec_int>(?P<dec_int_start>[1-9]\d{1,2}|[1-9]\d|[1-9])(?P<dec_int_end>\.\d{3})?,)|(?P<dec_short_int>[1-9]\d{2}|[5-9]\d),)(?=\d)(?P<frac_from_comma>(?<=,)(?P<frac>(?P<frac_end>\d{1,2})))?$
test
If you can guarantee that the number is correctly formed -- that is, that the regex isn't expected to detect that 5,0.1 is invalid, then there are a limited number of passing cases:
ends with \d{3}
ends with [5-9]\d
contains \d{3},
contains [5-9]\d,
It's not actually necessary to do anything with \.
The easiest regex is to code for each of these individually:
(\d{3}$|[5-9]\d$|\d{3},|[5-9]\d)
You could make it more compact and efficient by merging some of the cases:
(\d{3}[$,]|[5-9]\d[$,])
If you need to also validate the format, you will need extra complexity. I would advise against attempting to do both in a single regex.
However unless you have a very good reason for having to do this with a regex, I recommend against it. Parse the string into an integer, and compare it with 50.

Regular expression for 7 digit numbers separeted by commas

I need a regular expression to validate a concatenated string that consists of 7 digit numbers separated by commas.
Furthermore, I must ensure that:
The string is not empty.
The chain doesn't begins or finish with commas.
The numbers do not start with 0.
Example: 1234567,2345678,3456789
My solution so far: ^\d+(,\d+)*?$
The problems I still need to resolve:
Validate that the numbers are exactly 7 digits.
Validate that the numbers do not start with 0.
Thank you.
Something like ^[1-9]\d{6}(,[1-9]\d{6})+$ should work. The [1-9] ensures the number doesn't begin with 0, and \d{6} ensures that there are 6 digits to follow.
Based on Gavin answer, here is what worked for me : ^[1-9]\d{6}(,[1-9]\d{6})*$
The minor difference is the use of the * instead of + at the end of the regular expression. There are some cases where I must validate only one 7 digits number...
Thank you for the help everyone!

regular expression allows only decimal to enter

^(0)?[0-9]{0,}((\.){1}[0-9]{0,2}){0,1}$
The above regular expression allows me to enter numbers upto 4 decimal places with an optional 0 before the decimal(.) point. But it is not throwing error when I'm not entering numbers after decimal like 0., 12.,etc. !!!
Any guidance on this.
This is because you allow between 0 and 2 digits after the ..
Since you said you wanted between 1 and 4 digits, you probably want this:
^[0-9]*(\.[0-9]{1,4})?$
Note, I have replaced {0,} with * and {0,1} with ? as they are equivalent.
In addition, I've removed the {1}, as it matches one time per default.
The initial (0)? is also a bit redundant.
Beware, this regular expression matches .50. If you want to ensure that a number exists before the decimal point, change the first * to a + like so:
^[0-9]+(\.[0-9]{1,4})?$
To further simplify the regular expression, you can also replace [0-9] with \d in most regular expression engines, giving you:
^\d+(\.\d{1,4})?$
This regex could be simplified to the following:
^\d*(\.\d{1,4})?$
You can see it in action here: http://regexr.com?2vamh