topic Re: Use txt file as Fields in attribute table in Python Questions

Use txt file as Fields in attribute table

AleahWorthem — Sun, 05 Feb 2017 19:59:21 GMT

I am attempting to write a script so that instead of hardcoding the name of the new field as "CONFIVALUE" for the confidence value, I want to use the name of the third column in the header of the input text file.

For example, let's say that the first line of the input text file looks like this:

Latitude,Longitude,Confidence

In this case the field name should be "Confidence".

If the first line looked like this:

Latitude,Longitude,ConfidValue

Then the field name should be "ConfidValue".

The error if i have conField indexed as conField[2]:

Traceback (most recent call last):
File "C:\Users\Aleah\Desktop\PythonScripts\Lab7_Q5.py", line 22, in <module>
IndexError: list index out of range

The error i am receiving if i remove the index is:

Traceback (most recent call last):
File "C:\Program Files (x86)\Wing IDE 101 4.1\src\debug\tserver\_sandbox.py", line 27, in <module>
File "C:\Program Files (x86)\ArcGIS\Desktop10.3\arcpy\arcpy\management.py", line 3246, in AddField
raise e
RuntimeError: Object: Error in executing tool

import arcpy

    work = "C:\Scripts\Lab 7 Data\WildlandFires.mdb"
     arcpy.env.workspace = work # Set the workspace to the geodatabase
     arcpy.env.overwriteOutput = True

     iFile = "C:\Scripts\Lab 7 Data\NorthAmericaWildfires_2007275.txt"

     output = "NewFires.shp"
     threshold = 99

     f = open(iFile, 'r')# input text file C:\Scripts\Lab 7 Data\NorthAmericaWildfires_2007275.txt in "read" mode

lstFires = f.readlines() # Read the lines of fire
conField = []

     for line in f:
         comma = line.split(',')
         conField = comma
         print conField[2]

field = ["SHAPE@", conField[2]] # represents the field names for each row in the feature class
# Process: Create Feature Class

arcpy.CreateFeatureclass_management(work, output, "POINT")

arcpy.AddField_management(output, conField[2], "FLOAT")

cursor_new = arcpy.da.InsertCursor(output, field)# add the new points that you will create to the "NewFires" feature class

f.close() # close the file
del cursor_new # release the cursor lock on the feature class

Re: Use txt file as Fields in attribute table

DanPatterson_Retired — Mon, 06 Feb 2017 01:28:13 GMT

Aleah, perhaps you can format your code Code Formatting the Basics++

Re: Use txt file as Fields in attribute table

JoshuaBixby — Mon, 06 Feb 2017 02:43:13 GMT

Since "line 22" is generating the error, what exactly is line 22?

Also, does print conField[2] print the result you expect?

Re: Use txt file as Fields in attribute table

DanPatterson_Retired — Sat, 11 Dec 2021 13:16:29 GMT

comma = line.split(',')
conField = comma
print conField[2]‍‍‍

It appears to be a circular way around to splitting the line reference by the ',' then slicing it to get the last entry, it would be just as well be done as

conField= line.split(',')[2]‍

Re: Use txt file as Fields in attribute table

AleahWorthem — Mon, 06 Feb 2017 17:16:22 GMT

conField = []
for line in f:
conField = line.split(',')[2]

field = ["SHAPE@", conField] # represents the field names for each row in the feature class
# Process: Create Feature Class

arcpy.CreateFeatureclass_management(work, output, "POINT")

arcpy.AddField_management(output, conField, "FLOAT")

Traceback (most recent call last):
File "C:\Program Files (x86)\Wing IDE 101 4.1\src\debug\tserver\_sandbox.py", line 25, in <module>
File "C:\Program Files (x86)\ArcGIS\Desktop10.3\arcpy\arcpy\management.py", line 3246, in AddField
raise e
RuntimeError: Object: Error in executing tool

Re: Use txt file as Fields in attribute table

AleahWorthem — Mon, 06 Feb 2017 17:16:47 GMT

conField = []
for line in f:
conField = line.split(',')[2]

field = ["SHAPE@", conField] # represents the field names for each row in the feature class
# Process: Create Feature Class

arcpy.CreateFeatureclass_management(work, output, "POINT")

arcpy.AddField_management(output, conField, "FLOAT")

Re: Use txt file as Fields in attribute table

DarrenWiens2 — Sat, 11 Dec 2021 13:16:32 GMT

I assume that since you read all lines into the list, setting conField[2] to the third value in each line will ultimately result in the final value of your file, not the field name from the first line. You can access the first line of the file with f.readline() (reads only one line) or f.readlines()[0].

Also, you may be running into a problem if Python is reading a new line character at the end of your line. Try printing the split list to see the new line character:

>>> f = open(r'C:\junk\log.txt', 'r')
... my_list = f.readlines()
... print my_list[0]
... print my_list[0].split(',')
... 
field1,field2,field3

['field1', 'field2', 'field3\n']‍‍‍‍‍‍‍‍

Re: Use txt file as Fields in attribute table

JoshuaBixby — Sat, 11 Dec 2021 13:16:35 GMT

As Dan suggested, please use code formatting, It makes it easier for people to read and for specific comments about the code.

Your first line, cornfield = [], is unnecessary because str.split() returns a list.

You are using file.readlines(), emphasis on plural, that reads "until EOF." In your loop:

for line in f:
     conField = line.split(',')[2]‍‍

You are looping through the entire file contents, and by the time the loop finishes, conField contains the last line, not the first.

If you put a print statement after the loop is complete, what values are stored in conField?

Re: Use txt file as Fields in attribute table

AleahWorthem — Mon, 06 Feb 2017 17:59:46 GMT

f = open(iFile, 'r')# input text file C:\Scripts\Lab 7 Data\NorthAmericaWildfires_2007275.txt in "read" mode

lstFires = f.readlines() # Read the first lines of file

print (lstFires[0])
print (lstFires[0].strip().split(','))
This gives me :

Latitude,Longitude,Confidence

['Latitude', 'Longitude', 'Confidence']

But how can I access the Confidence string only, to be used later in arcpy.AddField_management

Re: Use txt file as Fields in attribute table

DanPatterson_Retired — Mon, 06 Feb 2017 18:30:49 GMT

con_val = lstFires[0].strip().split(',')[-1]

Re: Use txt file as Fields in attribute table

DarrenWiens2 — Mon, 06 Feb 2017 18:33:06 GMT

So, now that you've got rid of the new line character using strip(), you can access it similar to how you were doing it before, using the [2] index:

lstFires[0].strip().split(',')[2]‍

Re: Use txt file as Fields in attribute table

RandyBurton — Sat, 11 Dec 2021 13:16:37 GMT

Your code:

output = "NewFires.shp"
# ....
arcpy.CreateFeatureclass_management(work, output, "POINT")‍‍‍‍‍‍‍‍‍‍‍‍‍‍

I get an error 000354 : The name contains invalid characters (a table in a file geodatabase cannot include a space or a period).

But, you are using an Access database?

work = "C:\Scripts\Lab 7 Data\WildlandFires.mdb"‍

Re: Use txt file as Fields in attribute table

AleahWorthem — Mon, 06 Feb 2017 19:43:44 GMT

Syntax

CreateFeatureclass_management (out_path, out_name, {geometry_type}, {template}, {has_m}, {has_z}, {spatial_reference}, {config_keyword}, {spatial_grid_1}, {spatial_grid_2}, {spatial_grid_3})

the MDB seems to be working