I want to limit formatting.
- The length is 20
- the name does not contain special characters. like *,'%$^&.@#!~
- The image format is jpg, jpeg, png, gif, bmp, and webp
so i tried, I wrote it as below. However, I don't know to exclude special symbols. Help me bro!
'^(?!.{20}).*\.(?:gif|png|jpe?g|bmp|webp)$'
CodePudding user response：
if you want only file name to be with length 20 (without include extension) :
^(?:\w|\s|\d){20}\.(?:jpg|jpeg|png|gif|bmp|webp)$
else
^(?=(?:\w|\s|\d) \.(?:jpg|jpeg|png|gif|bmp|webp)).{20}$
CodePudding user response：
You can exclude what you want to allow to match using a negated character class, and repeat that 1-19 times if you want to make it less than 20 characters.
^[^*,'%$^&.@#!~\r\n]{1,19}\.(?:gif|png|jpe?g|bmp|webp)$