BUG: unsupported type Interval when writing dataframe to excel

Author: cbertinato

doc/source/whatsnew/v0.23.0.txt

@@ -549,3 +549,4 @@ Other
 ^^^^^
 
 - Improved error message when attempting to use a Python keyword as an identifier in a ``numexpr`` backed query (:issue:`18221`)
+- Bug in :func:`DataFrame.to_excel` where an exception was raised indicating unsupported type when writing a data frame containing a column of Interval type (:issue:`19242`)

pandas/io/excel.py

@@ -32,6 +32,7 @@
 from distutils.version import LooseVersion
 from pandas.util._decorators import Appender, deprecate_kwarg
 from textwrap import fill
+from pandas._libs.interval import Interval
 
 __all__ = ["read_excel", "ExcelWriter", "ExcelFile"]
 
@@ -788,6 +789,8 @@ def _conv_value(val):
         val = "{val}".format(val=val)
     elif is_list_like(val):
         val = str(val)
+    elif isinstance(val, Interval):
+        val = str(val)
 
     return val