Adding functional For loop Try/Catch example code

Hi Marcela, this is a working example of complex indexing that happens in the for loop and try blocks of the R SDG formatting code. I left in lines that helped me put the indexing together in pieces, and hopefully can help you understand the pieces of the long indexing call. These lines have "#FOR DEMO" written above them. It turns out the .item() calls at the end of some of the expressions are critical to prevent the mis-matched indexing errors we were getting earlier (they access the actual elements in the data structures returned by the expressions). The 'try' blocks are also essential I realized, because the lookup fails if a field collected sample has not yet been processed by the lab.
To incorporate this into the Python function, remove the #FOR DEMO lines, and add another indexing/assignment line with the correct column names substituted in the try block (so there should be a total of 2 assignment lines within each try block). Then make the 3 different try blocks like in the R code. Let me know if you have any questions!

SDG_FORLOOP_WITHTRYCATCH_TEMPLATE.PY

@@ -0,0 +1,31 @@
+for x in range(len(outputDF['waterSampleID'])):
+    # print(x)
+    # FOR DEMO
+    holder = outputDF.loc[outputDF.index[[x]], 'referenceAirSampleID']
+    # FOR DEMO
+    holder2 = externalLabData.loc[:, 'sampleID']
+    # Need to actually access the single cell value (string) in holder using .item()
+    # FOR DEMO
+    booleanHolder = holder2 == holder.item()
+    # FOR DEMO
+    holder3 = externalLabData.loc[booleanHolder, 'concentrationCO2']
+
+    # This is all of the above intermediate variables put together into one line, and is the right hand side of the
+    # assignment into the 'concentrationCO2Air' column of the outputDF data frame (at row 'x')
+    # FOR DEMO
+    rhsOfAssignment = externalLabData.loc[externalLabData.loc[:, 'sampleID'] == outputDF.loc[
+        outputDF.index[[x]], 'referenceAirSampleID'].item(), 'concentrationCO2']
+
+    # This needs to be in a try block because the outputDF has sampleIDs that are populated from the field samples,
+    # and this is looping through those sampleIDs to look for matches with the lab data, but for recently
+    # collected samples, there won't be lab data for them (but will obviously still be field samples) so this
+    # look-up will fail. Put it in a try block with nothing in the except block to imitate the silent try
+    # that this code has in R
+    try:
+        outputDF.loc[outputDF.index[[x]], 'concentrationCO2Air'] = externalLabData.loc[
+            externalLabData.loc[:, 'sampleID'] == outputDF.loc[
+                outputDF.index[[x]], 'referenceAirSampleID'].item(), 'concentrationCO2'].item()
+        # NEEDS THE OTHER ASSIGNMENT LINE HERE (THERE ARE 2 ASSIGNMENT LINES WITHIN EACH TRY BLOCK IN THE R CODE)
+
+    except Exception:
+        pass