I want to have a regex for:
- integer
- float
- max. 9 Digits
It is for Qt5
^[\d*[.,]?\d+]{0,4}$
without the {0,4} the regex works fine.
This Version works perfect, but i want to have max 9 digits
\d*[.,]?\d+
You may use
^(?!(?:\D*\d){10})\d*[.,]?\d+$
See the regex demo and the regex graph:
Details
^ - string start
(?!(?:\D*\d){10}) - fail the match if 10 or more digits is found
\d* - 0+ digits
[.,]? - an optional . or ,
\d+ - 1+ digits
$ - end of string.
This is a bit complicated. I'm also not so sure about the expression we would be wishing to design here, I'm guessing, we might want integers or floats with four digits, then we would be starting with a simple expression such as:
^\d{1,5}\.\d{1,4}$|^\d{1,9}$
The problem here would be this expression would also fail 111111.1, which is just one thing that would create sophistication. Another thing is that if we wish to also include commas.
Demo
RegEx Circuit
jex.im visualizes regular expressions:
Like Emma said, its complicated.
My suggestions is
(^\d{1}[,.]\d{1,8}$)|(^\d{2}[,.]\d{1,7}$)|(^\d{3}[,.]\d{1,6}$)|(^\d{4}[,.]\d{1,5}$)|(^\d{5}[,.]\d{1,4}$)|(^\d{6}[,.]\d{1,3}$)|(^\d{7}[,.]\d{1,2}$)|(^\d{8}[,.]\d{1,1}$)|(^\d{1,9}$)
First group checks all floats with one digit before the decimal point and 1 to 8 decimal places
Second group checks all floats with two digits before the decimal point and 1 to 7 decimal places
Third group checks all flaots with three digits before the decimal point and 1 to 6 decimal places
And so on...
The last group checks all integers with 1 to 9 digits
W/o ^ and $ in each group, it found the last 9 numbers in a 9+ digits number when using the multi line flag
jex.im
Related
I'm trying to create regex to retrieve last number if there was a number or any number if there wasn't any from a string.
Examples:
6 łyżek stopionego masła -> 6
5 łyżek blabla, 6 łyżek masła -> 6
5 łyżek mąki lub masła -> 5
I'm matching only on masła (changing variable) so it has to be included in regex
EDIT:
I cannot explain what I actually need:
Here is regex101 example: https://regex101.com/r/pEeRk3/1
EDIT2:
Emma's solution works great, but I would need to parse decimals and 2multiple digit numbers as well, meaning that those would match as well:
https://regex101.com/r/pEeRk3/3 - I added examples with answers in the link
If you want to match the last occurence of a digit with a decimal and you word has to follow this value, you might use lookarounds:
(?<!\S)\d+(?:\.\d+)?(?!\S)(?!.*\d)(?=.*masła)
(?<!\S)\d+(?:\.\d+)?(?!\S) Match 1+ digits with an optional past to match a dot and 1+ digits
(?!.*\d) assert that there are no more digits following
(?=.*masła) Assert what is on the right is your word
Regex demo
Or you might use a capturing group:
(?<!\S)(\d+(?:\.\d+)?)[^\d\n]* masła(?!\S)[^\d\n]*$
Regex demo
This expression might simply suffice:
.*([0-9])
if we are interested in one digit only, or
.*([0-9]+)
if multiple digits might be desired.
Demo 1
If those strings with masła are desired, we can expand our expression to:
(?=.*masła).*([0-9])
Demo 2
If we would not be validating our numbers and our number would be valid, with commas or dots, then this expression might likely return our desired output:
(?=.*masła)([0-9,.]+)(\D*)$
Demo 3
I am trying to figure out how to use regex to pass a 6 digit number string. My trouble is the string can be any 6 digits, unless it starts with 12. So the first digit can be 1 but not if second digit is 2. The second digit can be 2, but not if the first is 1.
I tried this, ([^1])([^2])(\d{4}) but that does not take into account both digits, so it will block anything with a 2 in the second spot.
Thank you for any help.
You may use
^([02-9][0-9]|[0-9][013-9])[0-9]{4}$
See the regex demo
Details:
^ - start of string
([02-9][0-9]|[0-9][013-9]) - either of the two alternatives:
[02-9][0-9] - any digit but 1 and then any digit
| - or
[0-9][013-9] - any digit and then any digit but 2
[0-9]{4} - any 4 digits
$ - end of string.
Another way is to use a negative lookahead:
^(?!12)[0-9]{6}$
See another demo. Here, (?!12) fails the match if the first 2 digits are 12. The [0-9]{6} will match 6 digits.
Depending on the regex library/method, ^/$ anchors may not be required. Lookaheads are not always supported, too.
I've come up with this regular expression to validate a number which can have Maximum length-13 (including decimal points),Maximum no of decimal points-3,Maximum length of a whole number-12.
^(\d{1,12}([.]\d{1,1})?|\d{1,11}([.]\d{1,2})?|\d{1,10}([.]\d{1,3})?)$
Could anyone tell me if my approach is correct or give me a better solution?
This would also work:
^(?=.{1,13}$)(\d{1,12})(\.\d{1,3})?$
Uses positive look ahead to match the entire string length is ok.
Then it uses a group to match from 1 - 12 digits
Then there's an optional group to match a decimal followed by 1-3 digits.
Edited: Simplified since the rules don't allow a 13 digit integer-part
I want except some numbers in different syntax and I am trying to find the best Regex for this task/match.
First some valid numbers:
0.01
0.2
0.38
45
165.6
52732.08
999999999.99
And here some invalid numbers:
.01
.2
.50
.85
45.
45.0
45.00
00045.0
124.60
000124.60
124,6
000053853.01
999.999.999,99
999999999,99
After several tests I have created the following Regex:
^[1-9]?\d{1,9}\.?\d{1,2}(?<!0)$
But I always struggling on the number: 000058723.01
Any ideas? Thanks.
You can use this regex:
^(?!0+\d)\d+(?:\.(?![1-9]*0+$)\d{1,2})?$
Or:
^(?:0+|[1-9]\d*)(?:\.(?![1-9]*0+$)\d{1,2})?$
RegEx Demo
Try this pattern:
^((?:0|[1-9]+)(?:\.(?:\d+?[1-9]|[1-9]))?)$
Demo
You accept four kinds of input:
A number with no decimal places and without leading zeroes: [1-9]\d*
Zero followed by a dot followed by digits (without trailing zeroes): 0\.\d*[1-9]
A decimal number without leading or trailing zeroes: [1-9]\d*\.\d*[1-9]
Zero: 0
Putting the four together:
^([1-9]\d*|0\.\d*[1-9]|[1-9]\d*\.\d*[1-9]|0)$
Here is a fixed version of your regex:
^(?!0{2,})\d+(?:\.\d{1,2}(?<!0))?$
Here, initial 2 or more zeros are not allowed with the lookahead (?!0{2,}), and the decimal part is made optional within a non-capturing group (?:\.\d{1,2}(?<!0))?.
See demo
In case you do not want to match 0, you can exclude this in the negative lookahead:
^(?!0{2,}|0$)\d+(?:\.\d{1,2}(?<!0))?$
^^
See Demo 2
A number with optional decimals is composed from two pieces: the integer part and the optional decimal part that starts with a dot.
The integer part is either zero (0) or a sequence of digits that start with 1..9 (no 0) and can continue with zero or more digits:
0|[1-9][0-9]*
If you need to impose an upper limit on the integer part's length then replace * with {,n} where n is the maximum allowed length minus 1.
The decimal part starts with a dot (.) followed by zero or more digits and followed by one of 1..9 (no 0 allowed at the end).
The expression is:
\.[0-9]*[1-9]
Now let's combine them:
^(0|[1-9][0-9]*)(\.[0-9]*[1-9])?$
What I added when I joined the pieces:
^ - match the start of the string; without this the regex matches 45.0 from 00045.0;
parentheses around the integer part because of the lower precedence of |;
parentheses around the decimal part, followed by ? to signal the entire decimal part is optional;
$ - match the end of the string to avoid matching 124.6 from 124.60.
Remarks
The above regex was designed to match your examples. However, please notice that most programming languages allow most or all of the numbers you put in the "invalid" section and use a dot (.) as decimal separator. And many languages provide library functions that are able to parse the numbers that use a comma (,) as decimal separator.
Numbers without integer part (.85), without digits after the dot (45.) ore with trailing zeros (45.0) are valid and are interpreted without ambiguity.
The only troublemaker is the leading zero (00045.0). For integer numbers, most of the times it is a signal that the number is represented in base 8 while for real numbers it is simply ignored.
I need to figure out how to make my regex allow match correctly each time I type a number/decimal point. I want to limit the number of digits before and after the decimal point, which isnt too hard but i cant figure out how to allow the decimal point to match as well.
1 - match
12 - match
1234 - match
12345 - wrong
1234. - match
1234.1 - match
1234.12 - match
1234.123 - wrong
Other matched numbers
12.12
1.0
123.99
Edit:
So I want a max of 4 numbers before the decimal place and two after. Also the decimal place is optional.
The tricky part is that I want it to fail if the fifth character isn't a decimal point.
You need to specify your constraints better; I'm assuming you want a maximum of 4 before the dot and 2 after:
/^\d{1,4}(\.\d{0,2})?$/
edit: I added beginning and end of string matchers. Should work as you want now
You can use the following regex to select only those words that consists of digits and satisfying your condition.
/(?<=^|\s)\d{1,4}(?:\.\d{0,2})?(?=\s|$)/g
Positive lookahead and lookbehind are used to make sure that a whitespace is around the number.
DEMO
Debuggex Demo
Something like this will help
r'^\d{1,4}(\.\d{0,2})?$'
As you must be aware, \d represents a digit, . for the decimal point and {min_required,max_required}. Be sure to test your regular expression prior to using them here.