topic Re: How to use CSV module write to multiple lines. in Python Questions

How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 10 Dec 2021 23:32:11 GMT

I have multiple lines but only one is written to the csv file. What am I missing from an except of my code.

s = (fullpath + lyr_source)
                    
                        with open('TEST.csv', 'w') as writeexcel:
                            a = csv.writer(writeexcel)
                            for line in :
                                a.writerow ([line])

Re: How to use CSV module write to multiple lines.

DarrenWiens2 — Thu, 26 May 2016 19:09:04 GMT

I'm not quite sure what you're trying to achieve here. What is the variable 's' - a file path string? If so, Python won't know to open it and read it, you need to actually read the file or table, for example, with a SearchCursor.

Re: How to use CSV module write to multiple lines.

BlakeTerhune — Fri, 10 Dec 2021 23:32:14 GMT

Try writerows() instead of writerow(). That works if you have all of your data in one Python iterable like a list of lists or tuples (no need to use it with a for loop). I use it when writing out from a SQL query. It also looks like you are missing a line to write your field names. And like Darren mentioned, your just using a path as your data, you need something to actually read it.

Here's the code I use for writing a feature class table out to a CSV line by line.

import arcpy
import os
import csv

# Environment variables
workingDir = r"C:\temp"
workingGDB = os.path.join(workingDir, "MyGeodatabase.gdb")
inputTable = os.path.join(workingGDB, "MyInputTable")
outputCSV = os.path.join(workingDir, "MyOutput.csv")

# Create CSV
with open(outputCSV, "w") as csvfile:
    csvwriter = csv.writer(csvfile, delimiter=',', lineterminator='\n')
    ## Write field name header line
    fields = ['FirstField','NextField','AndThirdExample']
    csvwriter.writerow(fields)
    ## Write data rows
    with arcpy.da.SearchCursor(inputTable, fields) as s_cursor:
        for row in s_cursor:
            csvwriter.writerow(row)

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Thu, 26 May 2016 20:04:14 GMT

The variable represents mxd/path/feaure class name, for all in a specified folder.

Example: C:\Users\me\Documents\xxxxx.mxdDatabaseConnections\PW_vCW_uCW.sde\PW.WDistribution\PW.wControlValve

I assigned a variable and trying to write it to csv file. You mentioned I need to read it. Is search cursor what I need or do I read it another way?

Re: How to use CSV module write to multiple lines.

DarrenWiens2 — Fri, 10 Dec 2021 23:32:17 GMT

Yes, if you're reading a simple system file, like a CSV, you can do so using something like csv.reader. GIS feature classes are somewhat more complex and specific, so you need to use a cursor that knows how to crack into the file structure. One such cursor for reading a feature class table is a SearchCursor, although there are other options outside of arcpy.

I'll just add an example why iterating through a file path string doesn't do much of anything:

>>> s = r'C:\junk.shp' # the string itself is an iterable
... for char in s: # loop through the items in s
...     print char # prints characters in s one at a time
...     
C
:
\
j
u
n
k
.
s
h
p

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 27 May 2016 14:40:38 GMT

Yes, thank you for clarifying.

I am trying this out and realizing that I can easily read an existing file and write to another, but my returned featureclass results requires something else.

I set a variable and I would get unusual results like you posted, vertically one character per cell,etc.

I will read up on Search Cursor and I am one step closer to what I need. I thought Search Cursor is only to return field names of feature classes and tables, which I want the feature class name and path.

To be cont...

Re: How to use CSV module write to multiple lines.

DanPatterson_Retired — Fri, 27 May 2016 14:49:12 GMT

Devin, are you using the csv module still? If so, check Blake's post, or maybe clarifying the title a bit might help.

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 27 May 2016 15:16:34 GMT

Yes, I am still trying csv module. I realize I have been going back and forth in a different post, for trying to find the easiest way.

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 27 May 2016 15:24:05 GMT

I modified with arcpy.da.SearchCursor(inputTable, fields) as s_cursor:

to with arcpy.da.SearchCursor(s,"") as s_cursor:

I don't want field names and the s is a variable I set for all feature classes/paths for mxds in a specified folder.

I get the following error when I run my script cannot open 'C:\CW\......

Does anyone know why? Thanks for your help in advance.

Re: How to use CSV module write to multiple lines.

BlakeTerhune — Fri, 27 May 2016 15:27:53 GMT

You have to give at least one field to the search cursor to get data for. You can leave out writing the field names in the CSV by removing line 16 from my code example above.

csvwriter.writerow(fields)

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 10 Dec 2021 23:32:19 GMT

I have the following and choose a random field name that is in one of the many feature classes I need returned.

I still have the error.

with open('TEST.csv', 'w') as csvfile:
                             csvwriter = csv.writer(csvfile, delimiter=',', lineterminator='\n')
                             fields = ['APN']
                             with arcpy.da.SearchCursor(s, fields) as s_cursor:
                                 for row in s_cursor: 
                                    csvwriter.writerow(fields)

Re: How to use CSV module write to multiple lines.

DarrenWiens2 — Fri, 27 May 2016 15:46:38 GMT

What is the error message?

edit: if you want to write the value of the current row, reference it in the row object.

csvwriter.writerow(row[0]) # would write the value in the first field in your field list

Re: How to use CSV module write to multiple lines.

BlakeTerhune — Fri, 27 May 2016 15:47:47 GMT

First, there's a nice way of posting code in GeoNet.

As for your error, first make sure you're building your paths correctly and that the feature class you're after actually exists. Also, check that last line in the code. You want to write each row to the csv, not fields.

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 27 May 2016 16:02:30 GMT

Traceback (most recent call last):

File "C:\Users\dunderwood\Desktop\LoopMXDListLayers.py", line 39, in <module>

with arcpy.da.SearchCursor(s, fields) as s_cursor:

RuntimeError: cannot open 'C:\...

Re: How to use CSV module write to multiple lines.

DarrenWiens2 — Fri, 27 May 2016 16:12:21 GMT

Look closely at Blake's example for writing a path:

workingDir = r"C:\temp"

The r denotes a raw string, which means '\t' is not interpreted as a tab, as it otherwise would. Is this how you're writing your paths?

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 27 May 2016 16:34:43 GMT

I have been looking at how to post code in geo net and building paths correctly. (Thanks Blake) I have only successfully formatted my original posting and still looking at building paths correctly.

I always use the raw as a path

r'C:\...'

Re: How to use CSV module write to multiple lines.

DarrenWiens2 — Fri, 27 May 2016 17:26:16 GMT

Please post your entire script, exactly as it is, including the full error message.

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 10 Dec 2021 23:32:22 GMT

# Import Modules
import arcpy,os,csv

#Set folder space
folder = r'C:\MY_TEMPLATES\CW'


#Loop All Mxd's in a folder and print out Info.

for filename in os.listdir(folder):
    fullpath = os.path.join(folder, filename)
    if os.path.isfile(fullpath):
        basename, extension = os.path.splitext(fullpath)
        if extension.lower() == ".mxd":
            mxd = arcpy.mapping.MapDocument(fullpath)
            dfs = arcpy.mapping.ListDataFrames(mxd)
            for df in dfs:
                layers = arcpy.mapping.ListLayers(mxd, "", df)
                for layer in layers:
                    if layer.isFeatureLayer:
                        lyr_source = layer.dataSource
                        lyr_name = layer.name.encode("utf8", "replace")
                        s = (fullpath + lyr_source)
                        print s
                        with open('TEST.csv', 'w') as csvfile:
                             csvwriter = csv.writer(csvfile, delimiter=',', lineterminator='\n')
                             fields = ['*']
                             with arcpy.da.SearchCursor(s, fields) as s_cursor:
                                 for row in s_cursor:  
                                    csvwriter.writerow(row)            
                           
#Close Excel File
csvfile.close()

print "Closed or Not: ",csvfile.closed

Run Script: (I get the following which I want looped to write to csv, but the cursor currently retrieves fields)

C:\MY_TEMPLATES\CW\CW_ENV_FMSE_EDIT.mxdDatabase Connections\CW_ENV_uCW_ENV_vCW_ENV.sde\PW.EnvironmentalCompliance\PW.ServiceEstablishments

Traceback (most recent call last):

File "C:\Users\dunderwood\Desktop\LoopMXDListLayers.py", line 30, in <module>

with arcpy.da.SearchCursor(s, fields) as s_cursor:

RuntimeError: cannot open 'C:\MY_TEMPLATES\CW\CW_ENV_FMSE_EDIT.mxdDatabase Connections\CW_ENV_uCW_ENV_vCW_ENV.sde\PW.EnvironmentalCompliance\PW.ServiceEstablishments'

Re: How to use CSV module write to multiple lines.

DarrenWiens2 — Fri, 27 May 2016 18:20:50 GMT

I'm confused by this line, which apparently concatenates two full file paths together:

s = (fullpath + lyr_source)

Does this work differently with SDE paths than regular file paths?

Re: How to use CSV module write to multiple lines.

DevinUnderwood2 — Fri, 27 May 2016 18:46:50 GMT

I want both so I get the mxd name and feature class path

fullpath is C:\Users\dunderwood\Documents\MY_TEMPLATES\CityWorks\CW_ENV_FMSE_EDIT.mxd

lyr_source is Database Connections\CW_ENV_uCW_ENV_vCW_ENV.sde\PW.EnvironmentalCompliance\PW.ServiceEstablishments

I am not sure SDE vs regular file path.