From b57af41e0f1d3201c3b1910fc3269f7cbafc527e Mon Sep 17 00:00:00 2001
From: Spencer Russell <spencer.russell@beacon.bio>
Date: Wed, 12 Jul 2023 22:38:34 -0400
Subject: [PATCH] more descriptive error message for `only`

---
 src/abstractdataframe/abstractdataframe.jl | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/abstractdataframe/abstractdataframe.jl b/src/abstractdataframe/abstractdataframe.jl
index 9dc47849a..af631da7d 100644
--- a/src/abstractdataframe/abstractdataframe.jl
+++ b/src/abstractdataframe/abstractdataframe.jl
@@ -517,7 +517,8 @@ If `df` has a single row return it as a `DataFrameRow`; otherwise throw `Argumen
 $METADATA_FIXED
 """
 function Base.only(df::AbstractDataFrame)
-    nrow(df) != 1 && throw(ArgumentError("data frame must contain exactly 1 row"))
+    n = nrow(df)
+    n != 1 && throw(ArgumentError("data frame must contain exactly 1 row, got $n"))
     return df[1, :]
 end