Raise exception if data frame to be written has NA values.

This should never occur, but can occur due to bugs in the code; we
wish to protect against that.

1 files changed, 2 insertions, 0 deletions

diff --git a/pyhegp/serialization.py b/pyhegp/serialization.py
index c197bf2..db1360a 100644
--- a/pyhegp/serialization.py
+++ b/pyhegp/serialization.py
@@ -108,6 +108,8 @@ def read_phenotype(file):
     return df
 
 def write_tsv(file, df):
+    if df.isna().any(axis=None):
+        raise ValueError("Data frame has NA values")
     df.to_csv(file,
               quoting=csv.QUOTE_NONE,
               sep="\t",