Regex to Match Digits and At Most One Space Between Them

Regex to match digits and at most one space between them

[\d ?]{7,12} is a pattern that matches 7 to 12 digit, space or ? chars. It can match a ??????? string because ? is not a quantifier, but a mere question mark symbol when declared inside a character class.

If you change it to (?:\d ?){7,12}, you may partially solve the problem, the space at the end. I suggest using

\b\d(?: ?\d){6,11}\b

See the regex demo

The word boundaries \b will make sure you only match whole words.

Details

• \b - leading word boundary
• \d - a digit
• (?: ?\d){6,11} - 6 to 11 consecutive sequences of
  
  
  • ? - an optional space
  • \d - a single digit
• \b - trailing word boundary.

Regex to match all groups between more than one space

You don't need to use look arounds here. Just use this regex to match a non-whitespace string or substring separated by a single space:

\S+(?:\s\S+)*

RegEx Demo

RegEx Details:

• \S+: Match 1+ non-space characters
• (?:\s\S+)*: Match 0 or more non-space substring separated by a single space.

Regex for two numbers and space between

You can try something like so: ^\d+(,\d+)?(\s\d+(,\d+)?)+$, example here.

This assumes that:

• The , is your floating point delimeter;
• Negative numbers aren't allowed.

EDIT

As per Wiktor's comment, this solution accepts two or more numbers separated by a white space. To only accept 2 numbers, the following needs to be used: ^\d+(,\d+)?(\s\d+(,\d+)?)$. (Notice the + at the end has been removed, changing the logic to 1 or more to just 1).

EDIT 2
As per your comment, if you need to match both the , and the . as separator, you would need to use something such as this: ^\d+([,.]\d+)?(\s\d+([,.]\d+)?)+$. This will accept both characters as decimal separators, however, please note that as is, can accept something of the sort: 12.34 34,56.

Regex match certain amount of character and allow space inbetween

Your ([0-9\ ?.?]{7,16}) expression matches 7 to 16 occurrences of any character that is either a digit, or a space, or a ?, or .. Yes, the ? inside [...] is a literal ?, not a quantifier.

You need to use an expression that will match a digit ([0-9]) and then exactly 7 sequences of a space or period ([ .]) followed with 1 digit, and to make sure you are not matching the digits in 123.156.78.146 you may use special boundaries:

(?<!\d[ .]?)\d(?:[. ]?\d){7}(?![ .]?\d)

if the space or . can only be 0 to 1 in between digits; or - if the space/dot can appear 0 or more times,

(?<!\d[ .]*)\d(?:[. ]*\d){7}(?![ .]*\d)

See the regex demo

The (?<!\d[ .]*) is a negative lookbehind that will fail any match if it starts with a digit that is followed with .(s) or space(s), and the (?![ .]*\d) negative lookahead will fail the match if the 7 digits you need are followed with .(s) or space(s) and a digit.

A regex to allow exactly 5 digit number with one optional white space before and after the number?

I might suggest just using lookarounds here:

/(?<![ ]{2})\b\d{5}\b(?![ ]{2})/

This pattern says to:

(?<![ ]{2})  assert that 2 (or more) spaces do NOT precede the ZIP code
\b\d{5}\b    match a 5 digit ZIP code
(?![ ]{2})   assert that 2 (or more) spaces do not follow

Here is a demo showing that the pattern works.

What is the regex for matching any numbers, with spaces between them?

The RegExp you're looking for is the following:

\b(\d+)\b

The above RegExp will match any number between two word boundaries, and, therefore, it will match:

• "123 "
• " 123"
• " 123 "

Use the g modifier to match all the occurrences (all the numbers). You can find a working example HERE.

JavaScript example:

var text = "12 Voorbeeld3 4Voorbeeld5 6 test 777",
    exp = /\b(\d+)\b/g,
    match;

while (match = exp.exec(text)) {
    console.log(match[0]);
}

Result:

12
6
777

Regular Expression - Ignore multiple spaces and Consider only one space in the match

You can match single spaces by editing your CircuitID part to either match a space character that isn't followed by another space character (?! ) (negative lookahead), or one of the non-space characters [a-zA-Z0-9\-\/].

so the CircuitID part becomes (?<CircuitID>(?:[a-zA-Z0-9\-\/]| (?! )){6,26})

regex101

How can I perform a regex that forces at least one space?

Based on your shown samples, could you please try following.

^(?=\S*\s)[\sa-zA-Z]{1,16}$

Explanation: Using positive look ahead to check if values other spaces coming 1 or more time followed by a space. Then using character class for space alphabets which will have 1 to 16 occurrences till end.

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