Controlling a script tool's progressor

Since script tools share the application, you have control of the progressor. You can control the appearance of the progressor by choosing either the default progressor or the step progressor.

To learn more about the progressor, see Understanding the progressor in script tools

The code below demonstrates full use of the default and step progressor. Copy this code into your Python editor, save it, then create a script tool for it. The script tool has two Long integer parameters as described in the code comments. Then run the script tool, providing different values for the parameters (start with n = 10 and p = 1, then try n = 101 and p = 3).

'''
Demonstration script showing examples of using the progressor
 Parameters:
   n - number to count to (a good first choice is 10)
   p - interval to count by (a good first choice is 1)
The various time.sleep() calls are just to slow the dialog down so you can view 
messages and progressor labels.
'''

import arcpy
import time

n = arcpy.GetParameter(0)
p = arcpy.GetParameter(1)

readTime = 2.5  # Pause to read what's written on dialog
loopTime = 0.3  # Loop iteration delay

arcpy.AddMessage("Running demo with: {} by {}\n".format(n, p))

# Start by showing the default progress dialog, where the progress bar goes 
# back and forth. Note how the progress label mimics working through some 
# "phases", or chunks of work that a script may perform.
arcpy.SetProgressor("default", "This is the default progressor")
time.sleep(readTime)

for i in range(1, 4):
    arcpy.SetProgressorLabel("Working on 'phase' {}".format(i))
    arcpy.AddMessage("Messages for phase {}".format(i))
    time.sleep(readTime)

# Setup the progressor with its initial label, min, max, and interval
arcpy.SetProgressor("step",
                    "Step progressor: Counting from 0 to {}".format(n),
                    0, n, p)
time.sleep(readTime)

# Loop issuing a new label when the increment is divisible by the value of 
# countBy (p). The "%" is Python's modulus operator - we only update the 
# position every p'th iteration.
for i in range(n):
    if (i % p) == 0:
        arcpy.SetProgressorLabel("Iteration: {}".format(i))
        arcpy.SetProgressorPosition(i)
        time.sleep(loopTime)

# Update the remainder that may be left over due to modulus operation.
arcpy.SetProgressorLabel("Iteration: {}".format(i + 1))
arcpy.SetProgressorPosition(i + 1)

arcpy.AddMessage("Done counting up\n")
time.sleep(readTime)

Choosing a good increment when maximum is potentially large

It's not at all uncommon to write scripts that will iterate an unknown number of times. For example, your script may use a arcpy.da.SearchCursor to iterate over all rows in a table, and you don't know the number of rows beforehand—your script may be used with tables of any size, from a few thousand rows to millions of rows. Incrementing a step progressor for every row in a large table is a performance bottleneck, and you may want to guard against such performance bottlenecks.

To demonstrate and assess performance issues with step progressors, copy the code below into your Python editor, save it, then create a script tool for it. The tool has two inputs: a table parameter and a field parameter. Run the script tool with a variety of table sizes, but be sure to try a table or feature class containing 10,000 or more rows to see performance differences.

The script executes three separate loops, and each loop fetches all the rows in the table. The loops differ in how they update the step progressor. The first and second loops update the step progressor in large increments, and the last loop increments the step progressor once for each row. When you run the tool, you see that this last loop takes longer to run.

You may want to employ the techniques found in this code for your script tools.

'''
Demonstrates a step progressor by looping through records on a table. Use a 
table with 10,000 or so rows - smaller tables will finish too quickly to assess.
   1 = table name
   2 = field on the table
'''

import arcpy
import time
import math

try:
    inTable = arcpy.GetParameterAsText(0)
    inField = arcpy.GetParameterAsText(1)

    # Determine number of records in table
    record_count = int(arcpy.GetCount_management(inTable)[0])
    if record_count == 0:
        raise ValueError("{} has no records to count".format(inTable))

    arcpy.AddMessage("Number of rows = {}\n".format(record_count))

    # Method 1: Calculate and use a suitable base 10 increment
    # ========================================================
    p = int(math.log10(record_count))
    if not p:
        p = 1
    increment = int(math.pow(10, p - 1))

    arcpy.SetProgressor(
        "step", "Incrementing by {} on {}".format(increment, inTable),
        0, record_count, increment)

    beginTime = time.clock()
    with arcpy.da.SearchCursor(inTable, [inField]) as cursor:
        for i, row in enumerate(cursor, 0):
            if (i % increment) == 0:
                arcpy.SetProgressorPosition(i)
            fieldValue = row[0]

    arcpy.SetProgressorPosition(i)
    arcpy.AddMessage("Method 1")
    arcpy.AddMessage("\tIncrement = {}".format(increment))
    arcpy.AddMessage("\tElapsed time: {}\n".format(time.clock() - beginTime))

    # Method 2: let's just move in 10 percent increments
    # ==================================================
    increment = int(record_count / 10.0)
    arcpy.SetProgressor(
        "step", "Incrementing by {} on {}".format(increment, inTable),
        0, record_count, increment)

    beginTime = time.clock()
    with arcpy.da.SearchCursor(inTable, [inField]) as cursor:
        for i, row in enumerate(cursor, 0):
            if (i % increment) == 0:
                arcpy.SetProgressorPosition(i)
            fieldValue = row[0]

    arcpy.SetProgressorPosition(i)
    arcpy.AddMessage("Method 2")
    arcpy.AddMessage("\tIncrement = {}".format(increment))
    arcpy.AddMessage("\tElapsed time: {}\n".format(time.clock() - beginTime))

    # Method 3: use increment of 1
    # ============================
    increment = 1
    arcpy.SetProgressor("step",
                        "Incrementing by 1 on {}".format(inTable),
                        0, record_count, increment)

    beginTime = time.clock()
    with arcpy.da.SearchCursor(inTable, [inField]) as cursor:
        for row in cursor:
            arcpy.SetProgressorPosition()
            fieldValue = row[0]

    arcpy.SetProgressorPosition(record_count)
    arcpy.ResetProgressor()
    arcpy.AddMessage("Method 3")
    arcpy.AddMessage("\tIncrement = {}".format(increment))
    arcpy.AddMessage("\tElapsed time: {}\n".format(time.clock() - beginTime))

    arcpy.AddMessage("Pausing for a moment to allow viewing...")
    time.sleep(2.0)  # Allow viewing of the finished progressor

except Exception as e:
    arcpy.AddError(e[0])