I have a string like:
$str1 = "12 ounces";
$str2 = "1.5 ounces chopped;
I'd like to get the amount from the string whether it is a decimal or not (12 or 1.5), and then grab the immediately preceding measurement (ounces).
I was able to use a pretty rudimentary regex to grab the measurement, but getting the decimal/integer has been giving me problems.
Thanks for your help!
If you just want to grab the data, you can just use a loose regex:
([\d.]+)\s+(\S+)
([\d.]+): [\d.]+ will match a sequence of strictly digits and . (it means 4.5.6 or .... will match, but those cases are not common, and this is just for grabbing data), and the parentheses signify that we will capture the matched text. The . here is inside character class [], so no need for escaping.
Followed by arbitrary spaces \s+ and maximum sequence (due to greedy quantifier) of non-space character \S+ (non-space really is non-space: it will match almost everything in Unicode, except for space, tab, new line, carriage return characters).
You can get the number in the first capturing group, and the unit in the 2nd capturing group.
You can be a bit stricter on the number:
(\d+(?:\.\d*)?|\.\d+)\s+(\S+)
The only change is (\d+(?:\.\d*)?|\.\d+), so I will only explain this part. This is a bit stricter, but whether stricter is better depending on the input domain and your requirement. It will match integer 34, number with decimal part 3.40000 and allow .5 and 34. cases to pass. It will reject number with excessive ., or only contain a .. The | acts as OR which separate 2 different pattern: \.\d+ and \d+(?:\.\d*)?.
\d+(?:\.\d*)?: This will match and (implicitly) assert at least one digit in integer part, followed by optional . (which needs to be escaped with \ since . means any character) and fractional part (which can be 0 or more digits). The optionality is indicated by ? at the end. () can be used for grouping and capturing - but if capturing is not needed, then (?:) can be used to disable capturing (save memory).
\.\d+: This will match for the case such as .78. It matches . followed by at least one (signified by +) digit.
This is not a good solution if you want to make sure you get something meaningful out of the input string. You need to define all expected units before you can write a regex that only captures valid data.
use this regular expression \b\d+([\.,]\d+)?
To get integers and decimals that either use a comma or a dot plus the next word, use the following regex:
/\d+([\.,]\d+)?\s\S+/
Related
I have developed the following regexp to capture float numbers.
([+-]?[0-9]+\.?[0-9]+([eE][-+]?[0-9]+)?)
It works fine for such things as 4.08955e-11 or 3.57. Now by stupid chance my parser came across 0 and failed. I guess I need to make all following the decimal point optional. But how do I do that?
Contrary to what one might think, matching every possible form of floating point number (including NaN etc) with a manageable regular expression that still discards e.g. impossibly large numbers or pseudo-octals is non-trivial.
There are some ideas about reducing the risk of false positives by using word boundaries, but note that those match boundaries between word characters (usually alphanumerics and underscore).
The scan command allows simple and reliable validation and extraction of floating point numbers:
scan $number %f
If you make all following the decimal point optional (which itself is optional) you could match values like 2.
Note that your regex does not match a single digit because you match 2 times one or more digits [0-9]+
If you only want to match float numbers or zero you could use an alternation and for example use word boundaries \b:
\b[-+]?(?:[0-9]+\.[0-9]+(?:[eE][-+]?[0-9]+)?|0)\b
Explanation
[-+]? Match optional + or -
\b Word boundary
(?: Non capturing group
[0-9]+\.[0-9]+ match one or more digits dot and one or more digits
(?:[eE][-+]?[0-9]+)? Optional exponent part
| Or
0 Match literally
) Close non capturing group
\b Word boundary
To match a float value that does not start with a dot and could be one or more digits without a dot you cold use use:
^[-+]?[0-9]+(?:\.[0-9]+)?(?:[eE][-+]?[0-9]+)?$
Perhaps using alternatives:
{[-+]?(?:\y[0-9]+(?:\.[0-9]*)?|\.[0-9]+\y)(?:[eE][-+]?[0-9]+\y)?}
I'm trying to apply a data validation formula to a column, checking if the content is a valid international telephone number. The problem is I can't have +1 or +some dial code because it's interpreted as an operator. So I'm looking for a regex that accepts all these, with the dial code in parentheses:
(+1)-234-567-8901
(+61)-234-567-89-01
(+46)-234 5678901
(+1) (234) 56 89 901
(+1) (234) 56-89 901
(+46).234.567.8901
(+1)/234/567/8901
A starting regex can be this one (where I also took the examples).
This regex match all the example you gave us (tested with https://fr.functions-online.com/preg_match_all.html)
/^\(\+\d+\)[\/\. \-]\(?\d{3}\)?[\/\. \-][\d\- \.\/]{7,11}$/m
^ Match the beginning of the string or new line.
To match (+1) and (+61): \(\+\d+\): The plus sign and the parentheses have to be escaped since they have special meaning in the regex. \d+ Stand for any digit (\d) character and the plus means one or more (the plus could be replaced by {1,2})
[\/\. \-] This match dot, space, slash and hyphen exactly one time.
\(?\d{3}\)?: The question mark is for optional parenthesis (? = 0 or 1 time). It expect three digits.
[\/\. \-] Same as step 3
[\d\- \.\/]{7,11}: Expect digits, hyphen, space, dot or slash between 7 and 11 time.
$ Match the end of the line or the end of the string
The m modifier allow the caret (^) and dollar sign ($) combination to match line break. Remove that if you want those symbol to match only the begining and the end of the string.
Slashes are use are delimiter for this regex (there are other character that you can use).
I must admit I don't like the last part of the regex as do not ensure that you have at least 7 digits.
It would be probably better to remove all the separator (by example with PHP function str_replace) and deal only with parenthesis and number with this regex
/(\(\+\d+\))(\(?\d{3}\)?)(\d{3})(\d{4})/m
Notice that in this last regex I used 4 capturing group to match the four digit section of the phone number. This regex keep the parenthesis and the plus sign of the first group and the optional parenthesis of the second group. To keep only the digits group, you can use this regex:
/\(\+(\d+)\)\(?(\d{3})\)?(\d{3})(\d{4})/m
Note: The groups are for formatting the phone number after validating it. It is probably better for you to keep all your phone number in your database in the same format.
Well, here are different possibility you can use.
Note: Those regex should be compatible with all regex engine, but it is good practice to specify with which language you works because regex engine don't deal the same way with advanced/fancy function.
By example, the look behind is not supported by javascript and .Net allow a more powerful control on lookbehind than PHP.
Keep me in touch if you need more information
I have a regular expression that I'm going to be using to verify that an inputted number is in standard U.S. telephone format (i.e (###) ###-####). I am new to regex and still having some trouble figuring out the exact function of each character. If someone would go through this piece by piece/verify that I am understanding I would really appreciate it. Also if the regex is wrong I would obviously like to know that.
\D*?(\d\D*?){10}
What I think is happening:
\D*?( indicates an escape sequence for the parenthesis metacharacter... not sure why the \D*? is necessary
\d indicating digits
\D*? indicating there is a non-digit character (-) followed by the closing parenthesis.
{10} for the 10 digits
I feel very unsure explaining this, like my understanding is very vague in terms of why the regex is in the order that it is etc. Thanks in advance for help/explanations.
EDIT
It seems like this is not the best regex for what I want. Another possibility was [(][0-9]{3}[)] [0-9]{3}-[0-9]{4}, but I was told this would fail. I suppose I'll have to do a little more work with regular expressions to figure this out.
\D matches any non-digit character.
* means that the previous character is repeated 0 or more times.
*? means that the previous character is repeated 0 or more times, but until the match of the following character in the regex. It is a bit difficult perhaps at the start, but in your regex, the next character is \d, meaning \D*? will match the least amount of characters until the next \d character.
( ... ) is a capture group, and is also used to group things. For instance {10} means that the previous character or group is repeated 10 times exactly.
Now, \D*?(\d\D*?){10} will match exactly 10 numbers, starting with non-digit characters or not, with non-digit characters in between the digits if they are present.
[(][0-9]{3}[)] [0-9]{3}-[0-9]{4}
This regex is a bit better since it doesn't just accept anything (like the first regex does) and will match the format (###) ###-#### (notice the space is a character in regex!).
The new things introduced here are the square brackets. These represent character classes. [0-9] means any character between 0 to 9 inclusive, which means it will match 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9. Adding {3} after it makes it match 3 similar character class, and since this character class contains only digits, it will match exactly 3 digits.
A character class can be used to escape certain characters, such as ( or ) (note I mentioned earlier they are for capturing groups, or grouping) and thus, [(] and [)] are literal ( and ) instead of being used for capturing/grouping.
You can also use backslashes (\) to escape characters. Thus:
\([0-9]{3}\) [0-9]{3}-[0-9]{4}
Will also work. I would also recommend the use of line anchors ^ and $ if you're only trying to see if a phone number matches the above format. This ensures that the string has only the phone number, and nothing else. ^ matches the beginning of a line and $ matches the end of a line. Thus, the regex will become:
^\([0-9]{3}\) [0-9]{3}-[0-9]{4}$
However, I don't know all the combinations of the different formats of phone numbers in the US, so this regex might need some tweaking if you have different phone number formats.
\D is "not a digit"; \d is "digit". With that in mind:
This matches zero or more non-digits, then it matches a digit and any number of non-digit characters 10 times. This won't actually verify that the number if formatted properly, just that it contains 10 digits. I suspect that the regex isn't what you want in the first place.
For example, the following will match your regex:
this is some bad text 1 and some more 2 and more 34567890
\D matches a character that is not a digit
* repeats the previous item 0 or more times
? find the first occurrence
\d matches a digit
so your group is matches 10 digits or non digits
I tried \b[0-9]{1,4}\.[0-9]{1,3}\.[0-9]{0,3} but it misses 34.89 and 23.89
I want all the number sequences in the text below except 28.72%
34.89
0105.93.10 ghghghh
0105.93.20 ghghhh
jjjjjhjj 0105.93.30 jsdfsd iksifsdjfk sdfsdk
0105.93.40ierfgg dfgkdfg dfgolgh 23.89
28.72%
Thanks
Paul
Your regex requires two dots to be present. You need to make the last dot-digit sequence optional, and you need to exclude matches where % or another digit follows (otherwise 28.7 within 28.72% would match):
\b[0-9]{1,4}\.[0-9]{1,3}(?:\.[0-9]{1,3})?(?![0-9%])
Make the last part optional
\b[0-9]{1,4}\.[0-9]{1,3}(?:\.[0-9]{0,3})?
Your original expression was requiring the period.
You were not very specific with your rules about matching %, so I made this:
\b[0-9]{1,4}\.[0-9]{1,3}(?:\.[0-9]{0,3})?(?=[^%\d]|$)
The last part is a positive lookahead for any non-% non-digit character or the end of the line. It needs to be non-digit as well or else 28.7 will match the rest of the expression, and the last 2 matches a non-percent character.
This will find all groups of numbers, separated by single dots, that are not followed by %:
(?:\d+\.)+\d+(?!\%)
It requires at least one digit on each side of a dot. Other than that, it doesn't care how many digits are in each group. At requires there be at least one dot in the number.
This would also require each group to have between 2 and 4 digits:
(?:\d{2,4}\.)+\d{2,4}(?!\%)
I am looking for some help on creating a regular expression that would work with a unique input in our system. We already have some logic in our keypress event that will only allow digits, and will allow the letter A and the letter M. Now I need to come up with a RegEx that can match the input during the onblur event to ensure the format is correct.
I have some examples below of what would be valid. The letter A represents an age, so it is always followed by up to 3 digits. The letter M can only occur at the end of the string.
Valid Input
1-M
10-M
100-M
5-7
5-20
5-100
10-20
10-100
A5-7
A10-7
A100-7
A10-20
A5-A7
A10-A20
A10-A100
A100-A102
Invalid Input
a-a
a45
4
This matches all of the samples.
/A?\d{1,3}-A?\d{0,3}M?/
Not sure if 10-A10M should or shouldn't be legal or even if M can appear with numbers. If it M is only there without numbers:
/A?\d{1,3}-(A?\d{1,3}|M)/
Use the brute force method if you have a small amount of well defined patterns so you don't get bad corner-case matches:
^(\d+-M|\d+-\d+|A\d+-\d+|A\d+-A\d+)$
Here are the individual regexes broken out:
\d+-M <- matches anything like '1-M'
\d+-\d+ <- 5-7
A\d+-\d+ <- A5-7
A\d+-A\d+ <- A10-A20
/^[A]?[0-9]{1,3}-[A]?[0-9]{1,3}[M]?$/
Matches anything of the form:
A(optional)[1-3 numbers]-A(optional)[1-3 numbers]M(optional)
^A?\d+-(?:A?\d+|M)$
An optional A followed by one or more digits, a dash, and either another optional A and some digits or an M. The '(?: ... )' notation is a Perl 'non-capturing' set of parentheses around the alternatives; it means there will be no '$1' after the regex matches. Clearly, if you wanted to capture the various bits and pieces, you could - and would - do so, and the non-capturing clause might not be relevant any more.
(You could replace the '+' with '{1,3}' as JasonV did to limit the numbers to 3 digits.)
^A?\d{1,3}-(M|A?\d{1,3})$
^ -- the match must be done from the beginning
A? -- "A" is optional
\d{1,3} -- between one and 3 digits; [0-9]{1,3} also work
- -- A "-" character
(...|...) -- Either one of the two expressions
(M|...) -- Either "M" or...
(...|A?\d{1,3}) -- "A" followed by at least one and at most three digits
$ -- the match should be done to the end
Some consequences of changing the format. If you do not put "^" at the beginning, the match may ignore an invalid beginning. For example, "MAAMA0-M" would be matched at "A0-M".
If, likewise, you leave $ out, the match may ignore an invalid trail. For example, "A0-MMMMAAMAM" would match "A0-M".
Using \d is usually preferred, as is \w for alphanumerics, \s for spaces, \D for non-digit, \W for non-alphanumeric or \S for non-space. But you must be careful that \d is not being treated as an escape sequence. You might need to write it \\d instead.
{x,y} means the last match must occur between x and y times.
? means the last match must occur once or not at all.
When using (), it is treated as one match. (ABC)? will match ABC or nothing at all.
I’d use this regular expression:
^(?:[1-9]\d{0,2}-(?:M|[1-9]\d{0,2})|A[1-9]\d{0,2}-A?[1-9]\d{0,2})$
This matches either:
<number>-M or <number>-<number>
A<number>-<number> or A<number>-A<number>
Additionally <number> must not begin with a 0.