diff --git a/qlib/utils/__init__.py b/qlib/utils/__init__.py
index 6334280ce8..433f82be76 100644
--- a/qlib/utils/__init__.py
+++ b/qlib/utils/__init__.py
@@ -518,7 +518,7 @@ def remove_fields_space(fields: [list, str, tuple]):
     """
     if isinstance(fields, str):
         return fields.replace(" ", "")
-    return [i.replace(" ", "") for i in fields if isinstance(i, str)]
+    return [i.replace(" ", "") if isinstance(i, str) else str(i) for i in fields]
 
 
 def normalize_cache_fields(fields: [list, tuple]):