Add helper method to PolyDict.constant to get constant term

1 files changed, 6 insertions, 0 deletions

diff --git a/polymatrix/polymatrix/index.py b/polymatrix/polymatrix/index.py
index d31e987..c906b35 100644
--- a/polymatrix/polymatrix/index.py
+++ b/polymatrix/polymatrix/index.py
@@ -155,6 +155,12 @@ class PolyDict(UserDict[MonomialIndex, int | float]):
             key = MonomialIndex(key)
         return super().__setitem__(key, value)
 
+    def constant(self) -> int | float:
+        """ Get the constant term of the polynomial. """
+        if MonomialIndex.constant() in self:
+            return self[MonomialIndex.constant()]
+        return 0
+
     def terms(self) -> Iterable[tuple[MonomialIndex, int | float]]:
         """ Iterate over terms with a non-zero coefficient. """
         # This is an alias for readability