Add a method to look up parameter by their nc_name, raise on non existent error name coercion

Author: DocOtak

CHANGELOG

@@ -1,3 +1,14 @@
+v2025.??.0 (2025-??-??)
+=======================
+Parameter Changes
+-----------------
+* None Yet
+
+API Changes
+-----------
+* (New) Add a method to look up parameter by their nc_name
+* (Potentially Breaking) Rise a `ValueError` when attempting to coerce a parameter into an error name when an error name it not defined for it
+
 v2025.10.0 (2025-10-31)
 =======================
 Parameter Changes

src/cchdo/params/__init__.py

@@ -144,6 +144,32 @@ def odv_names(self):
 
         return {to_odv(key): value for key, value in super().items()}
 
+    @cached_property
+    def _nc_names(self) -> dict[str, WHPName]:
+        return {param.nc_name: param for param in self.values()}
+
+    def from_nc_name(self, key: str) -> WHPName:
+        is_flag = key.endswith("_qc")
+        key = key.removesuffix("_qc")
+        is_error = key.endswith("_error")
+        key = key.removesuffix("_error")
+        depth = 0
+        if "_alt_" in key:
+            try:
+                _key, _depth = key.split("_alt_")
+                depth = int(_depth)
+                key = _key
+            except ValueError:
+                ...
+        param = self._nc_names[key]
+        if depth > 0:
+            param = param.as_depth(depth)
+        if is_flag:
+            return param.as_flag()
+        if is_error:
+            return param.as_error()
+        return param
+
     def __getitem__(self, key: WHPNameKey | WHPName) -> WHPName:
         unit = None
         flag = False

src/cchdo/params/core.py

@@ -137,6 +137,9 @@ def as_flag(self) -> "WHPName":
             raise ValueError("error columns cannot have flags")
         return replace(self, flag_col=True)
 
+    def as_base(self) -> "WHPName":
+        return replace(self, flag_col=False, error_col=False, alt_depth=0)
+
     @property
     def full_whp_name(self):
         if self.alt_depth > 0:
@@ -171,6 +174,10 @@ def odv_key(self) -> str:
         """
         if self.error_col:
             base = self.full_error_name
+            if base is None:
+                raise ValueError(
+                    f"Error name is not defined for this parameter {self.as_base()}"
+                )
         else:
             base = self.full_whp_name
 
@@ -182,7 +189,7 @@ def odv_key(self) -> str:
         if self.flag_col:
             key = f"{key}_FLAG_W"
 
-        return key
+        return str(key)
 
     @property
     def nc_name_flag(self) -> str: