I usually work with Arcpy but am trying to learn more pandas/geopandas uses. I have a mask applied to a csv table and a shapefile that I want to merge together in order to find matches between the two based on a specific field.
However, when I try to merge them together, I get the error “The truth value of a Dataframe is ambiguous.” How do I merge a masked dataframe? I’ve included the segment of code below that creates the mask (utilizing two date variables and a date field) and the merge which uses the Location fields (different names on each dataframe).
What do I need to do to manipulate the mask dataframe into functioning in a mask?
mask = (svc_df['createdate'] < curdate) & (svc_df['createdate'] >= backdate) print(svc_df.loc[mask]) # Detect the sub-dataframe and then assign to a new dataframe sel_df = svc_df.loc[mask] #Create a geodf from alabama services al_gdf = geopandas.read_file(alSvc_shp) al_merge = al_gdf.merge(al_gdf, sel_df, left_on="Location", right_on="sketch_LOC")
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Answer
- have synthesized a MWE from your code. Generation and data frame and geo data frame
- you have an error:
al_merge = al_gdf.merge(al_gdf, sel_df, left_on="Location", right_on="sketch_LOC")
- have used
dataframe.merge()
notpd.merge()
hence only one data frame should be passed as a parameter - full working example below
import pandas as pd import numpy as np import geopandas as gpd # synthesize svc_df = pd.DataFrame( { "createdate": pd.date_range("1-mar-2022", periods=30), "sketch_LOC": np.random.choice(["CHN", "USA", "IND", "JPN", "DEU"], 30), } ) curdate = pd.to_datetime("today") backdate = curdate - pd.Timedelta("5 days") mask = (svc_df["createdate"] < curdate) & (svc_df["createdate"] >= backdate) print(svc_df.loc[mask]) # Detect the sub-dataframe and then assign to a new dataframe sel_df = svc_df.loc[mask] # Create a geodf from alabama services # al_gdf = geopandas.read_file(alSvc_shp) # synthesize al_gdf = gpd.read_file(gpd.datasets.get_path("naturalearth_lowres")).assign( Location=lambda d: d["iso_a3"] ) al_merge = al_gdf.merge(sel_df, left_on="Location", right_on="sketch_LOC")