1 files changed, 18 insertions, 0 deletions
diff --git a/quality_control/checks.py b/quality_control/checks.py
index 28b9ab5..475eb9e 100644
--- a/quality_control/checks.py
+++ b/quality_control/checks.py
@@ -2,6 +2,8 @@
 import re
 from typing import Optional
 
+from .errors import InvalidValue
+
 def decimal_places_pattern(mini: int, maxi: Optional[int] = None) -> re.Pattern:
     """
     Generate a regular expression for checking numbers
@@ -49,3 +51,19 @@ def decimal_places_pattern(mini: int, maxi: Optional[int] = None) -> re.Pattern:
         + r"}"
         + r")$"
     )
+
+def decimal_points_error(lineno: int,
+                         field: str,
+                         value: str,
+                         mini: int,
+                         maxi: Optional[int] = None) -> Optional[InvalidValue]:
+    """
+    Check that 'value' in a decimal number with the appropriate decimal places.
+    """
+    if not bool(decimal_places_pattern(mini, maxi).match(value)):
+        return InvalidValue(lineno, field, value, (
+            f"Invalid value '{value}'. Expected numerical value " +
+            f"with at least {mini} decimal places" +
+            (f" and at most {maxi} decimal places" if maxi is not None else "")
+            + "."))
+    return None