For loop for access to a directory files in ArcPy

Question

I have a Python Toolbox and I want to use a directory to read different shapefiles. But when I run the script It only works for the first shape.

fd is the directory and the code is:

fd= parameters[0].valueAsText
raster= parameters[1].valueAsText

mar="Z:\\Datos_centralizados\\OSM_coastlines\\water_polygons.shp"
out= "Z:\\EMSV-057_AOIs_Reshape\\5_Process\\1_TaskA\\ModelBuilder\\MB_pruebas.gdb"
#-------------------------
    

#leemos los shapes de la carpeta y los metemos a una lista
    
flist = []
for root,folder,files in os.walk(fd):
        for file in files:
            if os.path.isfile(os.path.join(root,file)) and file.endswith('.shp'):
                flist.append(os.path.join(root,file))
            

for z in flist:
    shape=z

    # Cogemos datos alfanumericos del AOI
    desc = arcpy.Describe(shape)
    
    # aplicamos la herramienta Erase para quedarnos con la tierra
    erase=arcpy.Erase_analysis(shape,mar, out+"\\Tierra", cluster_tolerance="")
            
    
    # Estadisticos
    tZONA=arcpy.gp.ZonalStatisticsAsTable_sa(erase, "FID", raster, out+"\\tabla_Zona", "NODATA", "SUM") 
    

Answer 1

Here are four approaches. The first uses the arcpy Walk function. The second, third, and fourth approaches use built-in python modules. The fourth approach is the one you provided.

Here are the time benchmarks to recursively search a large directory:

Method 1:  15.0 seconds (arcpy.Walk)
Method 2: 140.0 seconds (os.Walk and fnmatch.filter)
Method 3:   4.0 seconds (glob.glob)
Method 4: 287.0 seconds (os.Walk)

Clearly Method 3 is the fastest--although this is because the search is relatively simple (i.e. looking for an extension that meets certain conditions). Note that method 3 requires the use of glob running Python 3. Method 1 is preferable if you need to isolate, for example point feature classes or other specific datatypes.

---

directory = r'C:\path\to\your\directory'

# Method 1 (Python 2.7)
import arcpy
import os

feature_classes = []

walk = arcpy.da.Walk(directory, datatype = "FeatureClass")

for dirpath, dirnames, filenames in walk:
    for filename in filenames:
        check = os.path.join(dirpath, filename)
        if os.path.isfile(check) and check.endswith(".shp"):
            feature_classes.append(os.path.join(dirpath, filename))

# Method 2 (Python 2.7)
import fnmatch
import os

matches = []
for root, dirnames, filenames in os.walk(directory):
    for filename in fnmatch.filter(filenames, '*.shp'):
        if os.path.isfile(os.path.join(root, filename)):
            matches.append(os.path.join(root, filename))

# Method 3 (Python 3.8)
import glob, os

shps = [x for x in glob.glob(os.path.join(directory, "**", "*.shp"), recursive = True) if os.path.isfile(x) and x.endswith(".shp")]

# Method 4 (Python 2.7)
import arcpy
import os

flist = []
for root,folder,files in os.walk(directory):
        for f in files:
            if os.path.isfile(os.path.join(root,f)) and f.endswith('.shp'):
                flist.append(os.path.join(root,f))