very close

app.py

@@ -34,6 +34,9 @@ def run():
     # initialize transcript DataFrame
     transcripts = pd.DataFrame(columns=[tiger.ID_COL, tiger.SEQ_COL])
 
+    # initialize results
+    st.session_state.on_target = st.session_state.off_target = None
+
     # manual entry
     if st.session_state.entry_method == ENTRY_METHODS['manual']:
         transcripts = pd.DataFrame({
@@ -58,27 +61,24 @@ def run():
     # convert to upper case as used by tokenizer
     transcripts[tiger.SEQ_COL] = transcripts[tiger.SEQ_COL].apply(lambda s: s.upper())
 
-    # make sure all transcripts only contain nucleotides A, C, G, T, and wildcard N
-    valid = transcripts[tiger.SEQ_COL].apply(lambda s: set(s).issubset(tiger.NUCLEOTIDE_TOKENS.keys()))
-    if not all(valid):
+    # check that all transcripts only contain nucleotides A, C, G, T, and wildcard N
+    if not all(transcripts[tiger.SEQ_COL].apply(lambda s: set(s).issubset(tiger.NUCLEOTIDE_TOKENS.keys()))):
         with TRANSCRIPT_ENTRY:
             st.write('Transcript(s) must only contain upper or lower case A, C, G, and Ts')
-        return
 
-    # make sure all transcripts satisfy length requirements
-    too_short = transcripts[tiger.SEQ_COL].apply(lambda s: len(s) < tiger.TARGET_LEN)
-    if any(too_short):
+    # check that all transcripts satisfy length requirements
+    elif any(transcripts[tiger.SEQ_COL].apply(lambda s: len(s) < tiger.TARGET_LEN)):
         with TRANSCRIPT_ENTRY:
             st.write('Transcript(s) must be at least {:d} bases.'.format(tiger.TARGET_LEN))
-        return
 
-    # run model
-    st.session_state.on_target, st.session_state.off_target = tiger.tiger_exhibit(
-        transcripts=transcripts,
-        mode={v: k for k, v in tiger.RUN_MODES.items()}[st.session_state.mode],
-        # status=RUNTIME,
-        check_off_targets=st.session_state.check_off_targets
-    )
+    # run model if we have any transcripts
+    elif len(transcripts) > 0:
+        st.session_state.on_target, st.session_state.off_target = tiger.tiger_exhibit(
+            transcripts=transcripts,
+            mode={v: k for k, v in tiger.RUN_MODES.items()}[st.session_state.mode],
+            # status=RUNTIME,
+            check_off_targets=st.session_state.check_off_targets
+        )
 
 
 if __name__ == '__main__':