arcgis-desktopfields-attributespythonqgisupdate
I have a Shapefile and a list in .csv which contains two columns with names:
How can I do this either on ArcGIS, QGIS or with python?
Based on this question I need to use the UpdateCursor function, but how can I use the list in this function?
If you need to write a lot of if statements you should consider using a dictionary instead. Code below will read a csv file and create a dictionary of names and codes and then use the dictionary in the Updatecursor for all shapefiles in a folder. Backup your data Before you try it:
import arcpy, csv
shapefile_folder = r'C:\folder'
arcpy.env.workspace = shapefile_folder
shapefile_fields_to_update = ["name","code"]
codefile = r"C:\Program123\codes.csv"
with open(codefile, 'r') as f:
reader = csv.reader(f)
dict = {k:v for (k,v) in reader} #Dictionary of names and codes is created here
for shapefile in arcpy.ListFeatureClasses():
with arcpy.da.UpdateCursor(shapefile, shapefile_fields_to_update) as cursor:
for row in cursor:
if row[0] in dict:
row[1]=int(dict[row[0]]) #And used here
cursor.updateRow(row)
else:
print "Name {0} not found in the dictionary, no update made for this name".format(row[0])
Here's how I would simplify this. To maintain a consistent number of columns it should write a blank value if the field doesn't exist.
import arcpy
import csv
arcpy.env.workspace = r"path\to\my\gdb"
newCSV = r"path\to\new\csv"
datasetList = arcpy.ListDatasets("*", "Feature")
label_name = 'feature_class'
csv_fields = [label_name, 'field1', 'field2', 'field3'] # define desired csv fields
with open(newCSV,'wb') as csvfile:
writer = csv.writer(csvfile) # only need to instantiate this once
writer.writerow(csv_fields) # write the header
for dataset in datasetList:
fcList = arcpy.ListFeatureClasses("*","",dataset)
for fc in fcList:
with arcpy.da.SearchCursor(fc, '*') as cursor: # include all available fields in the curor
for row in cursor:
record = dict(zip(cursor.fields, row)) # create a dict of field name to field value
record[label_name] = fc # add the feature class name to the dict
values = [record.get(key, None) for key in csv_fields] # build the csv row, using None as the default value
writer.writerow(values)
Best Answer
In QGIS you can perform Add Vector Join.
In ArcGIS it is very similar. You need to use Add Join tool.
More about joining in ArcGIS.