for loops with listLayers

Question

I have the following code to ouput all of my layers to pdfs. I'm trying to update the code from ArcMap to work in ArcGIS Pro. I'm not understanding the correct syntax to use for the curLayer line after the for loop starts. Please advise.

import sys
import arcpy
import os
import arcpy.mp as Map

# Set control parameters for map production
xDate = "April - 2024"  # Current data set being displayed (above legend on layout)
xPrint = "no"           # "yes"/"no" for print control
xFormat = "pdf"         # can be either pdf or png
xRes = 300              # resolution
pdfBook = "Viewer_MapBook_April_2024"  # Name of mapbook; disabled when format set to png
xDir = r"C:\Projects\Well Water Quality Viewer\make_web\Display_Maps\Display_Maps"  # Output directory
aprxFile = r"C:\Projects\Well Water Quality Viewer\make_web\Display_Maps\Display_Maps\Display_Maps.aprx"  # aprx document

# List of desired maps (in the order requested for mapbook)
maps = [
    'Alkalinity-Co', 'Arsenic-Co', 'Arsenic-Max-Co', 'Atrazine Family-Co', 'Bacteria-Co', 
    'Chloride-Co', 'Conductivity-Co', 'Copper-Co', 'Iron-Co', 'Lead-Co', 
    'Manganese-Co', 'Nitrate-Co', 'Nitrate Exceedence-Co', 'pH-Co', 'Saturation Index-Co', 
    'Sulfate-Co', 'Total Hardness-Co',
    'Alkalinity-TR', 'Arsenic-TR', 'Arsenic-Max-TR', 'Atrazine Family-TR', 'Bacteria-TR', 
    'Chloride-TR', 'Conductivity-TR', 'Copper-TR', 'Iron-TR', 'Lead-TR', 
    'Manganese-TR', 'Nitrate-TR', 'Nitrate Exceedence-TR', 'pH-TR', 'Saturation Index-TR', 
    'Sulfate-TR', 'Total Hardness-TR',
    'Alkalinity-S', 'Arsenic-S', 'Arsenic-Max-S', 'Atrazine Family-S', 'Bacteria-S', 
    'Chloride-S', 'Conductivity-S', 'Copper-S', 'Iron-S', 'Lead-S', 
    'Manganese-S', 'Nitrate-S', 'Nitrate Exceedence-S', 'pH-S', 'Saturation Index-S', 
    'Sulfate-S', 'Total Hardness-S',
]

# Set environment
arcpy.env.overwriteOutput = True
aprx = Map.ArcGISProject(aprxFile)
layout = aprx.listLayouts('PW_WEB_MAPPER')[0]
ms = layout.mapSeries
noteSet = layout.listElements("TEXT_ELEMENT", "Data_Set")[0]
noteSet.text = xDate

# Determine printing and PDF settings
dfList = aprx.listMaps("Layers")[0]

if xFormat != "pdf":
    xPrint = "no"
if xPrint == "no":
    mapPrint = "N"
else:
    mapPrint = "P"
if xFormat != "pdf":
    pdfBook = "no"
if pdfBook != "no":
    pdfDoc = Map.PDFDocumentCreate(os.path.join(xDir, pdfBook)+".pdf")

# Main loop
for xmap in maps:  
    curLayer = dfList.listLayers(dfList)[xmap]
    curLayer.visible = True
    Xport = os.path.join(xDir, xmap)
    if xFormat == "pdf":
        layout.exportToPDF(aprx, Xport, resolution=xRes)
        if pdfBook != "no":
            pdfDoc.appendPages(Xport + ".pdf")
    else:
        Map.ExportToPNG(aprx, Xport, resolution=xRes)

    if mapPrint == "P":
        Map.PrintMap(aprx)

    print("Exported: ", xmap)
    curLayer.visible = False

if pdfDoc != "no":
    pdfDoc.saveAndClose()
    del pdfDoc
del aprx
print("Script Complete")

Answer 1

dfList.listLayers(dfList) returns a python list, but xmap is a string. Lists can only be indexed using integers.

Before the loop, you could build a dict of layers then use that for the lookup instead:

layers = {layer.name: layer for layer in dfList.listLayers(dfList)}

for xmap in maps:
    try:
        curLayer = layers[xmap]
    except KeyError:
        print(f'layer "{xmap}" not found')
        continue