topic Re: HOW TO VALUE ROW COUNT? in Geoprocessing Questions

HOW TO VALUE ROW COUNT?

avidavid — Tue, 10 Mar 2015 15:19:28 GMT

I Have A Fc With A Field Which Contain
1,2,3 Value.

I Need To Write A Code That Give Me
The Total Count For Each Value:

1=29

2=52

3=57

this is the code:

print "start"

import arcpy

arcpy.env.overwriteOutput = 1

fc =r"D:\AVI_DAVID\zevel\zevel.gdb\Export_Output_miv_cur"

lst_field =arcpy.ListFields(fc,"USAGE") # usage is the field

for f in lst_field:

print f.name

DO I NEED A SEARCHCURSOR? OR
UPDATECURSOR?

AVI

Re: HOW TO VALUE ROW COUNT?

DanPatterson_Retired — Tue, 10 Mar 2015 20:53:12 GMT

See Summary Statistics if you have an Advanced license, check out the Frequency tool while you are there

Re: HOW TO VALUE ROW COUNT?

avidavid — Wed, 11 Mar 2015 07:54:47 GMT

Hi, Thank You For Your Answer. The
Frequency Tool Make A Tbl(Output) Which Is Good, But I Need The Result Inside
The Code

AVI

Re: HOW TO VALUE ROW COUNT?

avidavid — Wed, 11 Mar 2015 08:25:39 GMT

Do the same as Frequency( Frequency better)...

Re: HOW TO VALUE ROW COUNT?

DanPatterson_Retired — Sat, 11 Dec 2021 07:38:41 GMT

I am not sure what you mean by the result in the code...do you need the code to perform the task? If so, use the snippet from the help files or from the Results window after a successful run of the tool.

If need the actual results as a variable for further use in your code, you will have to use an arcpy.da searchcursor and I use numpy to do the grunt work. totally untested, but the sequence would be

After the help files on arcpy.da.searchcursor

Try this from the command line in your IDE

import arcpy
input_shp = 'c:/yourpath/yourfilename.shp'
input_field = 'num_field'   # an integer field as an example
values = [row[0] for row in arcpy.da.SearchCursor(input_shp, input_field)]
uniqueValues = set(values)  #from the help files

that will get you the values in the field, and their unique classes:

I tend to switch over to numpy if I already haven't converted the whole file to an array already.

>>> import numpy as np
>>> data = [1,2,2,2,1,1,1,3,3,2,3,3,4]
>>> classes = np.unique(data)
>>> freq = np.histogram(data,classes)
>>>
>>> classes
array([1, 2, 3, 4])
>>> freq
(array([4, 4, 5]), array([1, 2, 3, 4]))
>>>

which as you can see, there are 4 1's, four 2s, and 5 > 3

if you want an exact count, then you can play around with the bins as in this example

>>> data = [1,2,2,2,1,1,1,3,3,2,3,3,4]
>>> classes = np.unique(data)
>>> classes = np.unique(data).tolist()
>>> classes.append(classes[-1]+1)
>>> classes
[1, 2, 3, 4, 5]
>>> freq = np.histogram(data,classes)
>>> freq
(array([4, 4, 4, 1]), array([1, 2, 3, 4, 5]))
>>>

Of course, you can incorporate the command line stuff in your code