Regex that matches integers in between whitespace or start end of string only

Question

I m currently using the pattern   b d  b  testing it with these entries   numb3r  2 3454  3 214 test   I only want it to catch 2  and 3454  It works great for catching number words  except that the boundary flags   b  include     as consideration as a separate word  I tried excluding the period  but had troubles writing the pattern   Basically I want to remove integer words  and just them alone

User · Answer

Similar to manojlds but includes the optional negative/positive numbers:

var regex = /^[-+]?\d+$/;

EDIT

If you don't want to allow zeros in the front (023 becomes invalid), you could write it this way:

var regex = /^[-+]?[1-9]\d*$/;

EDIT 2

As @DmitriyLezhnev pointed out, if you want to allow the number 0 to be valid by itself but still invalid when in front of other numbers (example: 0 is valid, but 023 is invalid). Then you could use

var regex = /^([+-]?[1-9]\d*|0)$/

User · Answer

-   0-9  d  0     will accept numbers with leading      leading  -  and leadings  0

User · Answer

This worked in my case where I needed positive and negative integers that should NOT include zero-starting numbers like 01258 but should of course include 0     -  1-9   d     0    Example of valid values   3    -3    0    -555    945465464654   Example of not valid values   0 0    1 0    0 7    690 7    0 0001    a                  -    001    00 2    000 5     3    3      -1     100    --1    - 1    -0    00099    099

User · Answer

This solution matches integers   Negative integers are matched  -1 -2 etc  Single zeroes are matched  0  Negative zeroes are not  -0  -01  -02  Empty spaces are not matched          0 -  1-9   0-9

User · Answer

-    1-9  0-9    starts with a - or   for 0 or 1 times  then you want a non zero number  because there is not such a thing -0 or  0  and then it continues with any number from 0 to 9

User · Answer

All you want is the below regex     d

User · Answer

Try      -  1-9  d        0      It matches positive  negative numbers as well as zeros   It doesn t match input like 00  -0   0  -00   00  01   Online testing available at http   rubular com r FlnXVL6SOq

User · Answer

I would add this as a comment to the other good answers  but I need more reputation to do so  Be sure to allow for scientific notation if necessary  i e  3e4   30000  This is default behavior in many languages  I found the following regex to work      -    d   Ee   -   d                                   If  e  is present to denote exp notation  get it                               along with optional sign of exponent                               and the exponent itself                               The entire exponent expression is optional

User · Answer

This just allow positive integers     0-9   1-9  0-9

User · Answer

You could use lookaround instead if all you want to match is whitespace      lt   s    d     s

[regex] Regex that matches integers in between whitespace or start/end of string only

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