I am facing issues with regex pattern for Float number -> that should not end or stars with decimal points..
I have tried following regex patter.. that is
regex = /^\d*\.?\d*$/
// on doing
regex.test(11.)
regex.test(.11)
// it is returning true in checking
// I need to make this as false, comment will be much helpful
thank you.
You should bear in mind that regex only works with strings. When you pass a non-string variable as input to a RegExp, it will first coerce it to a string type.
Have a look:
console.log(11. , 'and', .11); // => 11 and 0.11
So, the actual string values you pass to your ^\d*\.?\d*$ regex are 11 and 0.11 that can be matched with the given pattern. Actually, ^\d*\.?\d*$ is a regex that is usually used for a very loose live number input validation, e.g. see How to make proper Input validation with regex?.
What you want is to implement a final, on-submit validation pattern, so that it could not pass strings like 11. and .11. There have been lots of threads discussing this kind of regex:
Regular expression for floating point numbers
regular expression for finding decimal/float numbers?
Basically, for validation, you will need something like
/^\d+(?:\.\d+)?$/.test(input_string)
/^[0-9]+(?:\.[0-9]+)?$/.test(input_string)
/^[0-9]+(?:\.[0-9]{1,2})?$/.test(input_string) // Some need to only allow 1 or 2 fractional digits
/^[0-9]{1,3}(?:\.[0-9]{2})?$/.test(input_string) // 1-3 digits in the integer part and two required in the fractional part
Related
I have an user input where user can edit price of something. To leave data consistance I would like to manipulate with that string on front-end site.
What I want to do is:
1234 to 1234.00
12.3 to 12.30
12,3 to 12.30
1234.45 to 1234.45
So basicly,
Replace comma with dots
this should be done easy with somehing like:
str.replace(',', '.');
Add dots if number if not decimal and also always change number of digits on two(so add 0 if needed)
I try to do something like:
priceByUser = priceByUser.replace(/^\d*\.?\d*$/, "$1\.00");
unfortunately this really doesnt even work as I expected.
Is there a chance someone can help me to solve this issue?
Thanks
You could consider using a regular expression to replace your commas and periods with just decimal points and then parse the values as floats via parseFloat() then finally, use the toFixed(2) function to indicate that you want two decimal places :
// This will clean up your input (consolidating periods and commas), parse the result
// as a floating point number and then format that number to two decimal places
priceByUser = parseFloat(priceByUser.replace(/,/g,'.')).toFixed(2);
If you wanted an extra-level of validation, you could consider stripping out any non-digit or decimal places after this occurs :
// Sanitize
priceByUser = priceByUser.replace(/,/g,'.').replace(/[^\d\.]/g,'');
// Parse and format
priceByUser = Number(priceByUser).toFixed(2);
Example
You can see a working example here and and example of input/output below :
how to validate numbers between 0 to 99999.99 using regex?
basically it should accept the values like 0.01, 0000.01, .01 and 9999.99
also it should have only two values after dot(.)
I tried something like the below but it did not work for me.
/^[0-9]{1,5}.[0-9]{2}$/
decimal is optional
Could someone help pls.
The . character has special meaning in a regex, so you need to escape it.
Anyway, let me see if I got the rules straight:
Decimal point is optional
If decimal point not given:
Between 1 and 5 digits
If decimal point is present:
Between 0 and 5 digits before decimal point
Between 1 and 2 digits after decimal point
Since the number of digits depends on the presence of the decimal point, you make the regex have two choices, separated by |.
Choice 1 (no decimal point): [0-9]{1,5}
Choice 2 (decimal point): [0-9]{0,5}\.[0-9]{1,2}
Since you want anchors (^$), you can either put them in both choices, or surround the choice set with parenthesis. To make it non-capturing, use (?:xxx).
Final regex is one of these:
/^[0-9]{1,5}$|^[0-9]{0,5}\.[0-9]{1,2}$/
/^(?:[0-9]{1,5}|[0-9]{0,5}\.[0-9]{1,2})$/
You can see the second one in effect on regex101.
If javascript then below regex would work:
^\d{0,5}(((\.){0})|((\.){1}\d{1,2}))$
All the above mentioned cases are satisfying.
Thank you and ^(?:\d{1,5}(?:\.\d{1,2})?|\.\d{1,2})$ is what i was trying to get and this serves my purpose.
Javascript regex:
/^\d{1,5}(\.\d{1,2})?$/
Javascript demo
i need a regular expression for decimal/float numbers like 12 12.2 1236.32 123.333 and +12.00 or -12.00 or ...123.123... for using in javascript and jQuery.
Thank you.
Optionally match a + or - at the beginning, followed by one or more decimal digits, optional followed by a decimal point and one or more decimal digits util the end of the string:
/^[+-]?\d+(\.\d+)?$/
RegexPal
The right expression should be as followed:
[+-]?([0-9]*[.])?[0-9]+
this apply for:
+1
+1.
+.1
+0.1
1
1.
.1
0.1
Here is Python example:
import re
#print if found
print(bool(re.search(r'[+-]?([0-9]*[.])?[0-9]+', '1.0')))
#print result
print(re.search(r'[+-]?([0-9]*[.])?[0-9]+', '1.0').group(0))
Output:
True
1.0
If you are using mac, you can test on command line:
python -c "import re; print(bool(re.search(r'[+-]?([0-9]*[.])?[0-9]+', '1.0')))"
python -c "import re; print(re.search(r'[+-]?([0-9]*[.])?[0-9]+', '1.0').group(0))"
You can check for text validation and also only one decimal point validation using isNaN
var val = $('#textbox').val();
var floatValues = /[+-]?([0-9]*[.])?[0-9]+/;
if (val.match(floatValues) && !isNaN(val)) {
// your function
}
This is an old post but it was the top search result for "regular expression for floating point" or something like that and doesn't quite answer _my_ question. Since I worked it out I will share my result so the next person who comes across this thread doesn't have to work it out for themselves.
All of the answers thus far accept a leading 0 on numbers with two (or more) digits on the left of the decimal point (e.g. 0123 instead of just 123) This isn't really valid and in some contexts is used to indicate the number is in octal (base-8) rather than the regular decimal (base-10) format.
Also these expressions accept a decimal with no leading zero (.14 instead of 0.14) or without a trailing fractional part (3. instead of 3.0). That is valid in some programing contexts (including JavaScript) but I want to disallow them (because for my purposes those are more likely to be an error than intentional).
Ignoring "scientific notation" like 1.234E7, here is an expression that meets my criteria:
/^((-)?(0|([1-9][0-9]*))(\.[0-9]+)?)$/
or if you really want to accept a leading +, then:
/^((\+|-)?(0|([1-9][0-9]*))(\.[0-9]+)?)$/
I believe that regular expression will perform a strict test for the typical integer or decimal-style floating point number.
When matched:
$1 contains the full number that matched
$2 contains the (possibly empty) leading sign (+/-)
$3 contains the value to the left of the decimal point
$5 contains the value to the right of the decimal point, including the leading .
By "strict" I mean that the number must be the only thing in the string you are testing.
If you want to extract just the float value out of a string that contains other content use this expression:
/((\b|\+|-)(0|([1-9][0-9]*))(\.[0-9]+)?)\b/
Which will find -3.14 in "negative pi is approximately -3.14." or in "(-3.14)" etc.
The numbered groups have the same meaning as above (except that $2 is now an empty string ("") when there is no leading sign, rather than null).
But be aware that it will also try to extract whatever numbers it can find. E.g., it will extract 127.0 from 127.0.0.1.
If you want something more sophisticated than that then I think you might want to look at lexical analysis instead of regular expressions. I'm guessing one could create a look-ahead-based expression that would recognize that "Pi is 3.14." contains a floating point number but Home is 127.0.0.1. does not, but it would be complex at best. If your pattern depends on the characters that come after it in non-trivial ways you're starting to venture outside of regular expressions' sweet-spot.
Paulpro and lbsweek answers led me to this:
re=/^[+-]?(?:\d*\.)?\d+$/;
>> /^[+-]?(?:\d*\.)?\d+$/
re.exec("1")
>> Array [ "1" ]
re.exec("1.5")
>> Array [ "1.5" ]
re.exec("-1")
>> Array [ "-1" ]
re.exec("-1.5")
>> Array [ "-1.5" ]
re.exec(".5")
>> Array [ ".5" ]
re.exec("")
>> null
re.exec("qsdq")
>> null
For anyone new:
I made a RegExp for the E scientific notation (without spaces).
const floatR = /^([+-]?(?:[0-9]+(?:\.[0-9]+)?|\.[0-9]+)(?:[eE][+-]?[0-9]+)?)$/;
let str = "-2.3E23";
let m = floatR.exec(str);
parseFloat(m[1]); //=> -2.3e+23
If you prefer to use Unicode numbers, you could replace all [0-9] by \d in the RegExp.
And possibly add the Unicode flag u at the end of the RegExp.
For a better understanding of the pattern see https://regexper.com/.
And for making RegExp, I can suggest https://regex101.com/.
EDIT: found another site for viewing RegExp in color: https://jex.im/regulex/.
EDIT 2: although op asks for RegExp specifically you can check a string in JS directly:
const isNum = (num)=>!Number.isNaN(Number(num));
isNum("123.12345678E+3");//=> true
isNum("80F");//=> false
converting the string to a number (or NaN) with Number()
then checking if it is NOT NaN with !Number.isNaN()
If you want it to work with e, use this expression:
[+-]?[0-9]+([.][0-9]+)?([eE][+-]?[0-9]+)?
Here is a JavaScript example:
var re = /^[+-]?[0-9]+([.][0-9]+)?([eE][+-]?[0-9]+)?$/;
console.log(re.test('1'));
console.log(re.test('1.5'));
console.log(re.test('-1'));
console.log(re.test('-1.5'));
console.log(re.test('1E-100'));
console.log(re.test('1E+100'));
console.log(re.test('.5'));
console.log(re.test('foo'));
Here is my js method , handling 0s at the head of string
1- ^0[0-9]+\.?[0-9]*$ : will find numbers starting with 0 and followed by numbers bigger than zero before the decimal seperator , mainly ".". I put this to distinguish strings containing numbers , for example, "0.111" from "01.111".
2- ([1-9]{1}[0-9]\.?[0-9]) : if there is string starting with 0 then the part which is bigger than 0 will be taken into account. parentheses are used here because I wanted to capture only parts conforming to regex.
3- ([0-9]\.?[0-9]): to capture only the decimal part of the string.
In Javascript , st.match(regex), will return array in which first element contains conformed part. I used this method in the input element's onChange event , by this if the user enters something that violates the regex than violating part is not shown in element's value at all but if there is a part that conforms to regex , then it stays in the element's value.
const floatRegexCheck = (st) => {
const regx1 = new RegExp("^0[0-9]+\\.?[0-9]*$"); // for finding numbers starting with 0
let regx2 = new RegExp("([1-9]{1}[0-9]*\\.?[0-9]*)"); //if regx1 matches then this will remove 0s at the head.
if (!st.match(regx1)) {
regx2 = new RegExp("([0-9]*\\.?[0-9]*)"); //if number does not contain 0 at the head of string then standard decimal formatting takes place
}
st = st.match(regx2);
if (st?.length > 0) {
st = st[0];
}
return st;
}
Here is a more rigorous answer
^[+-]?0(?![0-9]).[0-9]*(?![.])$|^[+-]?[1-9]{1}[0-9]*.[0-9]*$|^[+-]?.[0-9]+$
The following values will match (+- sign are also work)
.11234
0.1143424
11.21
1.
The following values will not match
00.1
1.0.00
12.2350.0.0.0.0.
.
....
How it works
The (?! regex) means NOT operation
let's break down the regex by | operator which is same as logical OR operator
^[+-]?0(?![0-9]).[0-9]*(?![.])$
This regex is to check the value starts from 0
First Check + and - sign with 0 or 1 time ^[+-]
Then check if it has leading zero 0
If it has,then the value next to it must not be zero because we don't want to see 00.123 (?![0-9])
Then check the dot exactly one time and check the fraction part with unlimited times of digits .[0-9]*
Last, if it has a dot follow by fraction part, we discard it.(?![.])$
Now see the second part
^[+-]?[1-9]{1}[0-9]*.[0-9]*$
^[+-]? same as above
If it starts from non zero, match the first digit exactly one time and unlimited time follow by it [1-9]{1}[0-9]* e.g. 12.3 , 1.2, 105.6
Match the dot one time and unlimited digit follow it .[0-9]*$
Now see the third part
^[+-]?.{1}[0-9]+$
This will check the value starts from . e.g. .12, .34565
^[+-]? same as above
Match dot one time and one or more digits follow by it .[0-9]+$
How can I extract and get just the numeric value after the hyphen in a string?
Here is the input string:
var x = "-2147467259"
After some processing.... return:
alert(2147467259)
How do I accomplish this?
You could replace away the hyphen:
alert(+x.replace("-", ""));
And yes, the + is important. It converts a string to a number; so you're removing the hypen by replacing it with nothing, and then essentially casting the result of that operation into a number. This operation will also work if no hyphen is present.
You could also use substr to achieve this:
alert(+x.substr(1));
You could also use parseInt to convert the string to a number (which will end up negative if a hyphen is persent), and then find its absolute value:
alert(Math.abs(parseInt(x, 10));
As Bergi notes, if you can be sure that the first character in the string is always a hyphen, you can simple return its negative, which will by default cast the value into a number and then perform the negative operation on it:
alert(-x);
You could also check to see if the number is negative or positive via a tertiary operator and then perform the respective operation on it to ensure that it is a positive Number:
x = x >= 0 ? +x : -x;
This may be cheaper in terms of performance than using Math.abs, but the difference will be minuscule either way.
As you can see, there really are a variety of ways to achieve this. I'd recommend reading up on JavaScript string functions and number manipulation in general, as well as examining JavaScript's Math object to get a feel for what tools are available to you when you go to solve a problem.
How about:
Math.abs(parseInt("-2147467259"))
Or
"-2147467259".replace('-','')
or
"-2147467259".replace(/\-/,'')
#1 option is converting the string to numbers. The #2 approach is removing all - from the string and the #3 option even though it will not be necessary on this example uses Regular Expression but I wanted to show the possibility of using RegEx in replace situations.
If you need a number as the final value #1 is your choice if you need strings #2 is your choice.
I have this code to test if a value entered in a INPUT is numeric:
$("#price").val().match(/^\d+$/);
I need some help rewriting this function to allow decimal places either with colon or dot meaning for example 230.00 is allowed and 230,00 is allowed too. Also the decimal places could be four or less. Any?
Regex: $("#price").val().match(/^\d+([,\.]\d{1,4})?$/);
Regex n2 with negative values: $("#price").val().match(/^-?\d+([,\.]\d{1,4})?$/);
If you need help parsing values related to some culture in specific, take a loot at this https://github.com/jquery/globalize. It's a library about globalization and localization.
Hope it helps!
$("#price").val().match(/^\d+((\.|,)\d+)?$/);
the above won't limit the number of decimal places to four, though.
By the way, that's a comma and not a "colon"
To match decimal places up to 4 only, use this
$("#price").val().match(/^\d+((\.|,)\d{1,4})?$/);
should match 1 to four numbers after . or ,