Reintroduce error handing and UI hints

app.py

@@ -7,27 +7,31 @@ st.set_page_config(page_title="Zero-shot classification from tabular data", page
 classifier = pipeline("zero-shot-classification", model="typeform/distilbert-base-uncased-mnli")
 
 st.title("Zero-shot classification from tabular data")
-st.text("Upload a table and perform zero-shot classification on a set of custom labels")
+st.text("Upload an Excel table and perform zero-shot classification on a set of custom labels")
 
-data = st.file_uploader("Upload Excel file:")
+data = st.file_uploader("Upload Excel file (it should contain a `text` column):")
 labels = st.text_input("Enter comma-separated labels:")
 
 if st.button("Calculate labels"):
 
-    labels_list = labels.split(",")
-    table = pd.read_excel(data)
-    table = table.loc[table["text"].apply(len) > 10].reset_index(drop=True).head(50)
+    try:
+        labels_list = labels.split(",")
+        table = pd.read_excel(data)
+        table = table.loc[table["text"].apply(len) > 10].reset_index(drop=True).head(50)
 
-    prog_bar = st.progress(0)
-    preds = []
+        prog_bar = st.progress(0)
+        preds = []
 
-    for i in range(len(table)):
-        preds.append(classifier(table.loc[i, "text"], labels)["labels"][0])
-        prog_bar.progress((i + 1)/len(table))
+        for i in range(len(table)):
+            preds.append(classifier(table.loc[i, "text"], labels)["labels"][0])
+            prog_bar.progress((i + 1)/len(table))
 
-    table["label"] = preds
+        table["label"] = preds
 
-    st.table(table[["text", "label"]])
+        st.table(table[["text", "label"]])
+
+    except:
+        st.error("File load didn't work. Make sure you upload a file containing a `text` column and a set of comma-separated labels is provided")