diff --git a/source/c02/p15_interpolating_variables_in_strings.rst b/source/c02/p15_interpolating_variables_in_strings.rst
index 42e03fe4..59c12412 100644
--- a/source/c02/p15_interpolating_variables_in_strings.rst
+++ b/source/c02/p15_interpolating_variables_in_strings.rst
@@ -106,7 +106,7 @@ Python并没有对在字符串中简单替换变量值提供直接的支持。
 
     >>> name = 'Guido'
     >>> n = 37
-    >>> '%{name} has %{n} messages.' % vars()
+    >>> '%{name}s has %{n}d messages.' % vars()
     'Guido has 37 messages.'
     >>>