gh-106318: Add example for str.isdecimal() (#137559)

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index f3a99c4448b9f33ded695b44bafda72f2c0039ba..7eb4f743d5abab332e2a495608484a5a0b3bc19b 100644 (file)
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -2073,9 +2073,18 @@ expression support in the :mod:`re` module).
    Return ``True`` if all characters in the string are decimal
    characters and there is at least one character, ``False``
    otherwise. Decimal characters are those that can be used to form
-   numbers in base 10, e.g. U+0660, ARABIC-INDIC DIGIT
+   numbers in base 10, such as U+0660, ARABIC-INDIC DIGIT
    ZERO.  Formally a decimal character is a character in the Unicode
-   General Category "Nd".
+   General Category "Nd". For example:
+
+   .. doctest::
+
+      >>> '0123456789'.isdecimal()
+      True
+      >>> '٠١٢٣٤٥٦٧٨٩'.isdecimal()  # Arabic-Indic digits zero to nine
+      True
+      >>> 'alphabetic'.isdecimal()
+      False
 
 
 .. method:: str.isdigit()