For each element, return True if there are only decimal characters in the element.
Calls unicode.isdecimal element-wise.
Decimal characters include digit characters, and all characters that that can be used to form decimal-radix numbers, e.g. U+0660, ARABIC-INDIC DIGIT ZERO.
| Parameters : | a : array_like, unicode 
  | 
|---|---|
| Returns : | out : ndarray, bool 
  | 
See also
unicode.isdecimal