On 2012-09-21 00:35, giuseppe.amatu...@gmail.com wrote:
Hi Ian and MRAB
thanks to you input i have improve the speed of my code. Definitely reading in
dic() is faster. I have one more question.
In the dic() I calculate the sum of the values, but i want count also the
number of observation, in order to calculate the average in the end.
Should i create a new dic() or is possible to do in the same dic().
Here in the final code.
Thanks Giuseppe
Keep it simple. Use 2 dicts.
rows = dsCategory.RasterYSize
cols = dsCategory.RasterXSize
print("Generating output file %s" %(dst_file))
start = time()
unique=dict()
for irows in xrange(rows):
valuesRaster=dsRaster.GetRasterBand(1).ReadAsArray(0,irows,cols,1)
valuesCategory=dsCategory.GetRasterBand(1).ReadAsArray(0,irows,cols,1)
for icols in xrange(cols):
if ( valuesRaster[0,icols] != no_data_Raster ) and (
valuesCategory[0,icols] != no_data_Category ) :
row = valuesCategory[0, icols],valuesRaster[0, icols]
if row[0] in unique :
unique[row[0]] += row[1]
else:
unique[row[0]] = 0+row[1] # this 0 was add if not the first
observation was considered = 0
You could use defaultdict instead:
from collections import defaultdict
unique = defaultdict(int)
...
category, raster = valuesCategory[0, icols],
valuesRaster[0, icols]
unique[category] += raster
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