I haven't tested this, but I assume that you could use something like this (although some sample data would be helpful):
def main():
import arcpy
# include path to PointwithGridNo
fc = r"C:\Folder\SubFolder\yourFGDB.gdb\PointwithGridNo"
# change names of fields according to your data
fld_gridno = "GridNo"
fld_elevation = "elevation"
fld_min = "min_elevation" # assuming this field already exists
fld_max = "max_elevation" # assuming this field already exists
# create dictionary with min and max values per GridNo
flds = (fld_gridno, fld_elevation)
dct_minmax = {}
with arcpy.da.SearchCursor(fc, flds) as curs:
for row in curs:
gridno = row[0]
elevation = row[1]
if gridno in dct_minmax:
min_elev = dct_minmax[gridno]["min"] if dct_minmax[gridno]["min"] < elevation else elevation
max_elev = dct_minmax[gridno]["max"] if dct_minmax[gridno]["max"] > elevation else elevation
dct_minmax[gridno] = {"min": min_elev, "max": max_elev}
else:
dct_minmax[gridno] = {"min": elevation, "max": elevation}
# use update cursor to update min and max elevation
flds = (fld_gridno, fld_min, fld_max)
with arcpy.da.SearchCursor(fc, flds) as curs:
for row in curs:
gridno = row[0]
if gridno in dct_minmax:
row[1] = dct_minmax[gridno]["min"]
row[2] = dct_minmax[gridno]["max"]
curs.updateRow(row)
if __name__ == '__main__':
main()
