Map algebra for loop

Question

I have never coded in Python before and I am trying to loop a simple map algebra equation across 365 rasters. I am trying to calculate total water flow over cells but in the raster I have a negative value to indicate the water table is below ground: for my purposes those cells should read 0. I have tried to write a for loop but it does not seem to be working. Python does not throw any errors, but the output data set still has negative numbers. Any suggestions on why the loop isn't working to remove the negative values?

arcpy.env.workspace="C:/..../2013_q1_tiff_v2prov"
Fcs= arcpy.ListRasters() 
From arcpy.sa import *
from arcpy.sa import *
print Fcs

for Raster in Fcs:
    Con(Raster <0, 0, Raster)

pleasework= CellStatistics(Fcs, "SUM")

Answer 1

This is because you are still referring to the original rasters when providing "Fcs" to the CellStatistics function. You need to store the results of your conditional statement and then refer to those, so something like this should work:

con_rasters = list()
for Raster in Fcs:
    temp_raster = Con(Raster <0, 0, Raster)
    con_rasters.append(temp_raster)

pleasework= CellStatistics(con_rasters, "SUM")