I am looking for a regex to validate the comma/space separated string (Allowing Alphanumeric and underscore) with the limit in each values to 64 and no of such values to 16.
var1,val2, val_3 val4 - valid
val*1, val&2 - Invalid due to illegal character
val1...65,val2, val3 val4 - invalid due to first value has 65 characters
val1,val2, val3 val4,...,val17 - invalid because no of values as more than 16
I have created a partial regex but there is some issue which I am not able to figure out.
^([0-9a-zA-Z_]{0,64}){1}(([,\s] )([0-9a-zA-Z_]{0-64})){0,15}$
CodePudding user response：
This part [0-9a-zA-Z_]{0,64} of the pattern can also match 0 times so it could also match an empty string.
You can omit {1} from the pattern, the notation in the second quantifier should be {0,64} instead of {0-64}
To get a match only, you can omit all the capture groups, and use a single repeating non capture group.
You might write the pattern as:
^\w{1,64}(?:[, \t] \w{1,64}){0,15}$
^Start of string\w{1,64}Match 1-64 word characters(?:Non capture group[, \t]Match either a comma, space or tab (or use[,\s])\w{1,64}Match 1-64 word characters
){0,15}Close the non capture group and repeat 0 - 15 times$End of string
Note that \s can also match a newline, so you could also use [,\s]