pandas df.to_json

JamesCrandall — Sat, 11 Dec 2021 22:16:55 GMT

I am converting a Feature class to a numpy array, to a pandas dataframe in order to peform some grouping and basic statistics (to determine percent of totals on Shape_Area). This is all working as expected and generating the desired result.

I need to publish this out as a GP service and for some reason it fails (no errors) to convert the grouped dataframe to_json(). It seems to "print" correctly in the python IDE,

[{"Landuse":"Dikes and Levees","pctOfTotal":0.84,"acreTotal":17.88},{"Landuse":"Fallow Cropland","pctOfTotal":98.5,"acreTotal":2094.91},{"Landuse":"Mixed Wetland Hardwoods","pctOfTotal":0.66,"acreTotal":14.01}]

but when output to arcpy.AddMessage it seems to print the dataframe instead of the JSON,

" Landuse pctOfTotal acreTotal\n0 Dikes and Levees 0.84 17.88\n1 Fallow Cropland 98.50 2094.91\n2 Mixed Wetland Hardwoods 0.66 14.01"

Full implementation:

narr = arcpy.da.FeatureClassToNumPyArray(clip_fc, flds)
df = pd.DataFrame(narr, columns=['Landuse','Shape_Area'])
grouped = df.groupby(['Landuse'])[['Shape_Area']].sum().reset_index()
grouped['pctOfTotal'] = (grouped['Shape_Area'] / grouped['Shape_Area'].sum()) * 100
grouped['acreTotal'] = grouped['Shape_Area'] / 43560
outJson = grouped.to_json(orient='records', default_handler = str)

print outJson #correctly formats as desired JSON
arcpy.AddMessage(outJson) #incorrectly displays it as a dataframe, not JSON
arcpy.SetParameter(1, outJson) #incorrectly outputs it as a dataframe, not JSON‍‍‍‍‍‍‍‍‍‍

Re: pandas df.to_json

EarlMedina — Fri, 19 Jul 2019 19:10:22 GMT

It looks like outJson is a list - maybe this is being misinterpreted by addMessage which expects a string? What happens if you create a string from outJson? Or I guess you see what happens if you just pass in the JSON string item in the list that the method creates and see what that does (i.e. outJson[0])

Re: pandas df.to_json

JamesCrandall — Fri, 19 Jul 2019 20:02:19 GMT

String would just output the df structure as a string.

I ended up converting to csv and then csv-to-json.

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pandas df.to_json

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