Round to nearest 100th

[ChrisBrannin]

I am a little confused about how to round a field to the nearest 100th. Would I use math.ceil() or the round()?

math.ceil([field]/100)*100

Does this only round down though?

Thanks

[MathewCoyle]

math.ceil() always rounds up. math.floor() rounds down. round() rounds the the nearest integer or to a particular decimal place if the second parameter is specified.

round([field], 2)

[ChrisBrannin]

I am a little confused about how to round a field to the nearest 100th. Would I use math.ceil() or the round()?

math.ceil([field]/100)*100

Does this only round down though?

Thanks

How I mean to phrase this question is, how to round a number (say 11) to 0 instead of 100?

[MathewCoyle]

How I mean to phrase this question is, how to round a number (say 11) to 0 instead of 100?

You would use a negative number for the second round() parameter of course. Use int() to ensure it returns an integer instead of float.

int(round([field], -2))

[ChrisBrannin]

You would use a negative number for the second round() parameter of course. Use int() to ensure it returns an integer instead of float.

int(round([field], -2))

That is the winner right there, thank you! I knew ther was a better way then to use math.ceil(). I really appreciate the help.

[ChrisBrannin]

You would use a negative number for the second round() parameter of course. Use int() to ensure it returns an integer instead of float.

int(round([field], -2))

How can I use this outside of arcmap? When I try, an error of "Invalid field [field]" appears.

I am trying to use it like this:

rndValue = "int(round(!ELEVATION!, -2))"

...

arcpy.CalculateField_management(elev, fieldName, rndValue, "PYTHON")

Thank you

[MathewCoyle]

That method works fine for me. Are you sure your field is the right type (long int)?

[ChrisBrannin]

That method works fine for me. Are you sure your field is the right type (long int)?

I had no issue with it in arcmap attribute table field calculator. Just in IDLE... My code below:

import arcpy
import os, math
from arcpy import env


in_workspace = r"F:/Inventory_export_dev/testRnd"
rndValue = "int(round(!ELEVATION!, -2))"
fcList = []
fieldName = "SL_ELEV"


for dirpath, dirnames, filenames in arcpy.da.Walk(in_workspace, datatype="FeatureClass",type="All"):
    for filename in filenames:
        fcList.append(os.path.join(dirpath, filename))


for list in fcList:
    arcpy.AddField_management(list, fieldName, "SHORT", "", "", "", "", "NULLABLE")


print "Rounding ELEVATION field to SL_ELEV"


#Rounds values from [ELEVATION] to [SL_ELEV]
for elev in fcList:
    arcpy.CalculateField_management(elev, fieldName, rndValue, "PYTHON")

am I missing something?

[MathewCoyle]

I would try printing out your elev value for each iteration of fcList to make sure it is what you expect.

[RhettZufelt]

Looks like you are trying to round the ELEVATION variable before you have set it to anything.

Need to either set it or extract it from the attributes first.

Also, both your for loops are working the same data, in one you assign it to list, in the other you assign to elev.  But, in both cases, you are still just itering through the values in fcList, so just as well do it in one swoop.

Think you are looking for something like this:

import arcpy
import os, math
from arcpy import env


in_workspace = r"F:/Inventory_export_dev/testRnd"
fcList = []



for dirpath, dirnames, filenames in arcpy.da.Walk(in_workspace, datatype="FeatureClass",type="All"):
    for filename in filenames:
        fcList.append(os.path.join(dirpath, filename))


for list in fcList:
    arcpy.AddField_management(list, fieldName, "SHORT", "", "", "", "", "NULLABLE")
    arcpy.CalculateField_management(list, "SL_ELEV", "int(round( !ELEVATION!, -2))", "PYTHON")

Haven't tested, but should go through each FC in your fcList add the field and populate it with the round value.

R_