my first lookahead (or lookbehind?) exercise - regex

8:9 DAR4:3], 23.98 fps
8:9 DAR4:3], 29.97 fps
8:9 DAR4:3], 25 fps
I've got these 3 possible strings, and I'm looking for an expression that will extract the numbers which occur between the first comma in this line, and the " fps".
either 23.98, 29.97, 25
How best to attack this? Looking behind to whatever digits and dots [\d.] fall before " fps" seems the most logical way but I've never done one of these.
An example, please?
I have this already,
\d{2}\.\d{2}|25
but I'm afraid the "25" could pick up false positives from somewhere later in the text.

,\s*(\d+\.?\d*)\s*fps$
Edit live on Debuggex
Maybe this will work?
, indicates the the comma
\s* indicates zero or more spaces.
(\d+\.?\d*) captures decimal values in a capture group
\s* indicates zero or more spaces.
fps$ checks to see if fps is at the end of the line.

(?<=, )[0-9]+(\.[0-9]+)?(?= fps)
should work fine and will only match your numbers.
Regex101 demo

Related

How to create a matching regex pattern for "greater than 10-000-000 and lower than 150-000-000"?

I'm trying to make
09-546-943
fail in the below regex pattern.
​^[0-9]{2,3}[- ]{0,1}[0-9]{3}[- ]{0,1}[0-9]{3}$
Passing criteria is
greater than 10-000-000 or 010-000-000 and
less than 150-000-000
The tried example "09-546-943" passes. This should be a fail.
Any idea how to create a regex that makes this example a fail instead of a pass?
You may use
^(?:(?:0?[1-9][0-9]|1[0-4][0-9])-[0-9]{3}-[0-9]{3}|150-000-000)$
See the regex demo.
The pattern is partially generated with this online number range regex generator, I set the min number to 10 and max to 150, then merged the branches that match 1-8 and 9 (the tool does a bad job here), added 0? to the two digit numbers to match an optional leading 0 and -[0-9]{3}-[0-9]{3} for 10-149 part and -000-000 for 150.
See the regex graph:
Details
^ - start of string
(?: - start of a container non-capturing group making the anchors apply to both alternatives:
(?:0?[1-9][0-9]|1[0-4][0-9]) - an optional 0 and then a number from 10 to 99 or 1 followed with a digit from 0 to 4 and then any digit (100 to 149)
-[0-9]{3}-[0-9]{3} - a hyphen and three digits repeated twice (=(?:-[0-9]{3}){2})
| - or
150-000-000 - a 150-000-000 value
) - end of the non-capturing group
$ - end of string.
This expression or maybe a slightly modified version of which might work:
^[1][0-4][0-9]-[0-9]{3}-[0-9]{3}$|^[1][0]-[0-9]{3}-[0-9]{2}[1-9]$
It would also fail 10-000-000 and 150-000-000.
In this demo, the expression is explained, if you might be interested.
This pattern:
((0?[1-9])|(1[0-4]))[0-9]-[0-9]{3}-[0-9]{3}
matches the range from (0)10-000-000 to 149-999-999 inclusive. To keep the regex simple, you may need to handle the extremes ((0)10-000-000 and 150-000-000) separately - depending on your need of them to be included or excluded.
Test here.
This regex:
((0?[1-9])|(1[0-4]))[0-9][- ]?[0-9]{3}[- ]?[0-9]{3}
accepts (space) or nothing instead of -.
Test here.

Detecting whole number with an "x" or "-" after using regex

I'm trying to use regex to detect the quantity in a list of items on a receipt. The software uses OCR so the return can vary a bit. To help ive narrowed it to assume that the quantity will always be at the start of the line and is always a whole number. The use cases I'm trying to cover are:
2 Burgers $4.00
2 x Burgers $4.00
2 X Burgers $4.00
2x Burgers $4.00
2X Burgers $4.00
2- Burgers $4.00
2 - Burgers $4.00
The plan is for the regex to return 2 for each example above. The regex I have so far is \\d{1,2}(\\s[xX]|[xX]) this returns the top three examples fine but as much as I have tried I cant seem to get the rest detected, I haven't looked at adding the - yet as was stuck on detecting the x next to the Int.
Any help would be great, thanks
To help ive narrowed it to assume that the quantity will always be at the start of the line and is always a whole number.
I suggest using something like
let pattern = "(?m)^\\d+"
See the regex demo.
The pattern will match 1 or more digits at the start of any line:
(?m) - a MULTILINE modifier that makes ^ match the start of a line rather than the start of a string
^ - start of a line
\d+ - 1 or more (+) digits.
If you need to specify that some text should follow the digits, use a positive lookahead. E.g. you may require x/X/- after 0+ whitespaces, or a whitespace right after. Then, you need to use
let pattern = "(?m)\\d+(?=\\s*[xX-]|\\s)"
Here, (?=\\s*[xX-]|\\s) will make the regex match only those digits at the start of the line(s) that are immediately followed with either 0+ whitespace chars and then X, x or -, or that are immediately followed with a whitespace.
See this regex demo.
^(\\d+)\\s?[xX-]?.*?([$£](?:\\d{1,2})(?:,?\\d{3})*\.?\\d{0,2})$
See it working here (extra backslashes have been added in the code above to allow it to work in Swift, whereas the below link shows the expected result in JS, Python, Go and PHP, which means there are less backslashes there).
Will capture number of items and the price, what the item is is not captured.

Regex for validation of a street number

I'm using an online tool to create contests. In order to send prizes, there's a form in there asking for user information (first name, last name, address,... etc).
There's an option to use regular expressions to validate the data entered in this form.
I'm struggling with the regular expression to put for the street number (I'm located in Belgium).
A street number can be the following:
1234
1234a
1234a12
begins with a number (max 4 digits)
can have letters as well (max 2 char)
Can have numbers after the letter(s) (max3)
I came up with the following expression:
^([0-9]{1,4})([A-Za-z]{1,2})?([0-9]{1,3})?$
But the problem is that as letters and second part of numbers are optional, it allows to enter numbers with up to 8 digits, which is not optimal.
1234 (first group)(no letters in the second group) 5678 (third group)
If one of you can tip me on how to achieve the expected result, it would be greatly appreciated !
You might use this regex:
^\d{1,4}([a-zA-Z]{1,2}\d{1,3}|[a-zA-Z]{1,2}|)$
where:
\d{1,4} - 1-4 digits
([a-zA-Z]{1,2}\d{1,3}|[a-zA-Z]{1,2}|) - optional group, which can be
[a-zA-Z]{1,2}\d{1,3} - 1-2 letters + 1-3 digits
or
[a-zA-Z]{1,2} - 1-2 letters
or
empty
\d{0,4}[a-zA-Z]{0,2}\d{0,3}
\d{0,4} The first groupe matches a number with 4 digits max
[a-zA-Z]{0,2} The second groupe matches a char with 2 digit in max
\d{0,3} The first groupe matches a number with 3 digits max
You have to keep the last two groups together, not allowing the last one to be present, if the second isn't, e.g.
^\d{1,4}(?:[a-zA-z]{1,2}\d{0,3})?$
or a little less optimized (but showing the approach a bit better)
^\d{1,4}(?:[a-zA-z]{1,2}(?:\d{1,3})?)?$
As you are using this for a validation I assumed that you don't need the capturing groups and replaced them with non-capturing ones.
You might want to change the first number check to [1-9]\d{0,3} to disallow leading zeros.
Thank you so much for your answers ! I tried Sebastian's solution :
^\d{1,4}(?:[a-zA-z]{1,2}\d{0,3})?$
And it works like a charm ! I still don't really understand what the ":" stand for, but I'll try to figure it out next time i have to fiddle with Regex !
Have a nice day,
Stan
The first digit cannot be 0.
There shouldn't be other symbols before and after the number.
So:
^[1-9]\d{0,3}(?:[a-zA-Z]{1,2}\d{0,3})?$
The ?: combination means that the () construction does not create a matching substring.
Here is the regex with tests for it.

How can I use RegEx to differentiate between screen resolutions?

I'm trying to create a RegEx expression that will match a numeric range from 0 to 600 so I can easily differentiate between a small mobile device and tablets/desktops. I'm using Qualtrics' survey software to do the rest - all I need is the RegEx expression.
However, I'm not 100% sure how Qualtrics takes in the data. I believe it takes it in the following format:
360x640
320x568
320x480
1920x1080
360x640
1280x800
320x568
1920x1080
360x640
1280x800
1920x1080
480x800
320x480
1280x800
1366x768
320x568
1280x800
Where I'm testing the FIRST number, e.g. the number before the 'x' character.
Here's some RegEx I've tried that did not work:
([0-9]{1,2}|[1-4][0-9]{2}|600)*x
That code recognizes numbers before the 'x', but it doesn't stop at 600 - it recognizes all numbers before the 'x' (e.g. from 000 to 9999).
How do I get the range I want? Please and thank you!
Note: I've tried using the RegEx number range generator here, but it doesn't work for what I want to accomplish.
I'd do:
\b(?:600|[1-9]\d?|[1-5]\d{2})x
Where:
\b is a word boundary, it makes sure there're no digits before
(?: ) is a non capture group
600 matches 600
[1-9]\d? matches number from 1 to 99
[1-5]\d{2} matches number from 100 to 599
I don't believe there are width lower than 100, so you can use this pattern:
^([1-5][0-9]{2}|600)x
You can use this regex but with m modifier if your input contains all those lines together:
^([0-5]\d{2}|600)x
Live demo

Need to capture single character, but ignore digit

I'm parsing out flight info.
Here's the sample data:
E0.777 7 3:09
E0.319 N 1:43
E0.735 8 1:45
E0.735 N 1:48
E0.M80 9 3:21
E0.733 1:48
I need to populate fields like this:
Equipment: 735
On Time: N
Duration: 1:48
Problem I'm having is capturing the Y or N character but ignoring the single digit, then capturing the duration.
This is the expression I have tried:
#"^.{3}(.{3})\s?([N|Y]?)?(?:[0-9]\s+)?(\w{4})"
Edit: I updated the sample data to clarify my question. Equipment is not always three digits, it could be a character and two digits. The data between the equipment and the duration could be a boolean N or Y, a single digit, or white space. Only the boolean should be captured.
Firstly, you mix up the concepts of alternation and character classes [Y|N] would match 3 different characters: Y or | or N. Either use (...) or leave out the pipe.
Secondly your double ? after the character class does not really do anything. Thirdly, at the end you only match consecutive spaces if a digit was found. But if there is no digit, the last ? will ignore the subpattern, thus not allowing spaces either.
Lastly, \w does not match :.
Try this:
#"^.{3}(\d{3})\s?(?:([NY])|\d)\s+(\d:\d\d)"
You should also think about restricting the repeated . at the beginning to a more precise character class (i.e \w{2}\., but I don't know the possibilities there).
#"^..\.(\d{3})\s(?:([YN])|\d)\s*(\S{4})"
Changed .{3} to ..\. which is a bit more specific about there being a literal . for character 3.
(?:([YN])|\d) matches either Y/N or a digit, but only captures a Y or N. Notice that it's [YN] not [Y|N].
Changed \w{4} to \S{4} since \w doesn't match colons :.
This will do it...
^\w\d\.(\d{3})\s(?:([YN])|\d)\s*(\d:\d{2})$
I made some other changes to your regex because it was easier for me to just rewrite it based off your data then to try to modify what you had.
This will capture the Y or N or it won't capture anything in that group. I also tried to be more specific with your duration regex.
Update: This works with your new requirements...
^\w\d\.(\w{3})\s(?:([YN])|\d|\s)\s*(\d:\d{2})$
You can see it working on your data here... http://regexr.com?32j1b
(hover over each line to see the matched groups)
This captures all lines with Y or N and ignores everything else:
^...(\d{3})\s*([YN])\s*(\d+:\d+)