Remove Extra Commas From Beginning or Ending of a String

A simple and very short code to replace extra commas from the beginning or ending of a string. No need to explain the code.

DECLARE @str VARCHAR(50) = ',a,n,i,s,h,'

SELECT @str

SET @str = REPLACE(@str, ',', ' ')

SET @str = LTRIM(RTRIM(@str))

SELECT  REPLACE(@str,' ', ',')