Using python in field calculator to extract highest value from 3 columns
I have three columns, one for percentage White, percentage Hispanic, and percentage African American per census tract. I'm trying to use python to extract the population subtype with the highest percentage into a new column called "highest_percentage". The highest percentage category will have 3 classes: 1,2, and 3. I can not figure out how to set a conditional statement so that I can automatically assign a value of 1,2, or 3 to the census tract to use in a classified map. Any help would be appreciated! I was able to write code to find the highest percentage and assign the new field the same value as that percentage, but i'm trying to find which field has the highest value and assign it 1-3 based on a classification. 3 white, 2 Hispanic, 1 African American
I've attached a screenshot of the table and the code window below.
arcmap field-calculator python-parser
edited 3 hours ago
PolyGeo♦
53.5k1780239
asked 4 hours ago
JohnJohn
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I have three columns, one for percentage White, percentage Hispanic, and percentage African American per census tract. I'm trying to use python to extract the population subtype with the highest percentage into a new column called "highest_percentage". The highest percentage category will have 3 classes: 1,2, and 3. I can not figure out how to set a conditional statement so that I can automatically assign a value of 1,2, or 3 to the census tract to use in a classified map. Any help would be appreciated! I was able to write code to find the highest percentage and assign the new field the same value as that percentage, but i'm trying to find which field has the highest value and assign it 1-3 based on a classification. 3 white, 2 Hispanic, 1 African American
I've attached a screenshot of the table and the code window below.
arcmap field-calculator python-parser
edited 3 hours ago
PolyGeo♦
53.5k1780239
asked 4 hours ago
JohnJohn
112
New contributor
John is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Welcome to GIS SE! We're a little different from other sites; this isn't a discussion forum but a Q&A site. Please check out our short tour to learn about our focussed Q&A format. Please always present any code using formatted text (highlight it use the {} button) rather than pictures.
– PolyGeo♦
2 hours ago
add a comment |
I have three columns, one for percentage White, percentage Hispanic, and percentage African American per census tract. I'm trying to use python to extract the population subtype with the highest percentage into a new column called "highest_percentage". The highest percentage category will have 3 classes: 1,2, and 3. I can not figure out how to set a conditional statement so that I can automatically assign a value of 1,2, or 3 to the census tract to use in a classified map. Any help would be appreciated! I was able to write code to find the highest percentage and assign the new field the same value as that percentage, but i'm trying to find which field has the highest value and assign it 1-3 based on a classification. 3 white, 2 Hispanic, 1 African American
I've attached a screenshot of the table and the code window below.
arcmap field-calculator python-parser
edited 3 hours ago
PolyGeo♦
53.5k1780239
asked 4 hours ago
JohnJohn
112
New contributor
John is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I have three columns, one for percentage White, percentage Hispanic, and percentage African American per census tract. I'm trying to use python to extract the population subtype with the highest percentage into a new column called "highest_percentage". The highest percentage category will have 3 classes: 1,2, and 3. I can not figure out how to set a conditional statement so that I can automatically assign a value of 1,2, or 3 to the census tract to use in a classified map. Any help would be appreciated! I was able to write code to find the highest percentage and assign the new field the same value as that percentage, but i'm trying to find which field has the highest value and assign it 1-3 based on a classification. 3 white, 2 Hispanic, 1 African American
I've attached a screenshot of the table and the code window below.
arcmap field-calculator python-parser
arcmap field-calculator python-parser
edited 3 hours ago
PolyGeo♦
53.5k1780239
asked 4 hours ago
JohnJohn
112
New contributor
John is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 3 hours ago
PolyGeo♦
53.5k1780239
asked 4 hours ago
JohnJohn
112
New contributor
John is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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edited 3 hours ago
PolyGeo♦
53.5k1780239
edited 3 hours ago
PolyGeo♦
53.5k1780239
edited 3 hours ago
PolyGeo♦
53.5k1780239
53.5k1780239
asked 4 hours ago
JohnJohn
112
New contributor
John is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 4 hours ago
JohnJohn
112
asked 4 hours ago
JohnJohn
112
112
New contributor
John is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
John is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
John is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Welcome to GIS SE! We're a little different from other sites; this isn't a discussion forum but a Q&A site. Please check out our short tour to learn about our focussed Q&A format. Please always present any code using formatted text (highlight it use the {} button) rather than pictures.
– PolyGeo♦
2 hours ago
add a comment |
Welcome to GIS SE! We're a little different from other sites; this isn't a discussion forum but a Q&A site. Please check out our short tour to learn about our focussed Q&A format. Please always present any code using formatted text (highlight it use the {} button) rather than pictures.
– PolyGeo♦
2 hours ago
Welcome to GIS SE! We're a little different from other sites; this isn't a discussion forum but a Q&A site. Please check out our short tour to learn about our focussed Q&A format. Please always present any code using formatted text (highlight it use the {} button) rather than pictures.
– PolyGeo♦
2 hours ago
Welcome to GIS SE! We're a little different from other sites; this isn't a discussion forum but a Q&A site. Please check out our short tour to learn about our focussed Q&A format. Please always present any code using formatted text (highlight it use the {} button) rather than pictures.
– PolyGeo♦
2 hours ago
add a comment |
2 Answers
2
active
oldest
votes
Try this
Pre-Logic Script Code:
def maxnum(fields):
max_value=fields[0]
return_value=1
if (fields[1]>max_value):
max_value=fields[1]
return_value=2
if (fields[2]>max_value):
max_value=fields[2]
return_value=3
return return_value
trav_tracts.highest_percent=
maxnum([!trac_tracts.percent_aa!,!trav_tracts.percent_hispanic!,!trac_tracts.percent_white!])
answered 3 hours ago
Tayyab MirTayyab Mir
311
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I prefer to use an arcpy UpdateCursor for tasks such as these, mainly because I think the syntax is easier to work with and can be incorporated into larger workflows.
In your case, find the index of the largest percentage in each row. For example:
import arcpy
fc = r'C:pathtoyourfile_geodatabase.gdbfeatureclass'
with arcpy.da.UpdateCursor(fc, ("african_american", "hispanic", "white", "index")) as cursor:
for row in cursor:
max_val = max(row) # Find the max value in each row
max_index = row.index(max_val) # Find the index of the max value
row[3] = max_index + 1 # Apply a correction on the index
cursor.updateRow(row)
answered 2 hours ago
Aaron♦Aaron
37.9k19109253
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Try this
Pre-Logic Script Code:
def maxnum(fields):
max_value=fields[0]
return_value=1
if (fields[1]>max_value):
max_value=fields[1]
return_value=2
if (fields[2]>max_value):
max_value=fields[2]
return_value=3
return return_value
trav_tracts.highest_percent=
maxnum([!trac_tracts.percent_aa!,!trav_tracts.percent_hispanic!,!trac_tracts.percent_white!])
answered 3 hours ago
Tayyab MirTayyab Mir
311
New contributor
Tayyab Mir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
Try this
Pre-Logic Script Code:
def maxnum(fields):
max_value=fields[0]
return_value=1
if (fields[1]>max_value):
max_value=fields[1]
return_value=2
if (fields[2]>max_value):
max_value=fields[2]
return_value=3
return return_value
trav_tracts.highest_percent=
maxnum([!trac_tracts.percent_aa!,!trav_tracts.percent_hispanic!,!trac_tracts.percent_white!])
answered 3 hours ago
Tayyab MirTayyab Mir
311
New contributor
Tayyab Mir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
Try this
Pre-Logic Script Code:
def maxnum(fields):
max_value=fields[0]
return_value=1
if (fields[1]>max_value):
max_value=fields[1]
return_value=2
if (fields[2]>max_value):
max_value=fields[2]
return_value=3
return return_value
trav_tracts.highest_percent=
maxnum([!trac_tracts.percent_aa!,!trav_tracts.percent_hispanic!,!trac_tracts.percent_white!])
answered 3 hours ago
Tayyab MirTayyab Mir
311
New contributor
Tayyab Mir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Try this
Pre-Logic Script Code:
def maxnum(fields):
max_value=fields[0]
return_value=1
if (fields[1]>max_value):
max_value=fields[1]
return_value=2
if (fields[2]>max_value):
max_value=fields[2]
return_value=3
return return_value
trav_tracts.highest_percent=
maxnum([!trac_tracts.percent_aa!,!trav_tracts.percent_hispanic!,!trac_tracts.percent_white!])
answered 3 hours ago
Tayyab MirTayyab Mir
311
New contributor
Tayyab Mir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 3 hours ago
Tayyab MirTayyab Mir
311
New contributor
Tayyab Mir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 3 hours ago
Tayyab MirTayyab Mir
311
answered 3 hours ago
Tayyab MirTayyab Mir
311
311
New contributor
Tayyab Mir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Tayyab Mir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Tayyab Mir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
I prefer to use an arcpy UpdateCursor for tasks such as these, mainly because I think the syntax is easier to work with and can be incorporated into larger workflows.
In your case, find the index of the largest percentage in each row. For example:
import arcpy
fc = r'C:pathtoyourfile_geodatabase.gdbfeatureclass'
with arcpy.da.UpdateCursor(fc, ("african_american", "hispanic", "white", "index")) as cursor:
for row in cursor:
max_val = max(row) # Find the max value in each row
max_index = row.index(max_val) # Find the index of the max value
row[3] = max_index + 1 # Apply a correction on the index
cursor.updateRow(row)
answered 2 hours ago
Aaron♦Aaron
37.9k19109253
add a comment |
I prefer to use an arcpy UpdateCursor for tasks such as these, mainly because I think the syntax is easier to work with and can be incorporated into larger workflows.
In your case, find the index of the largest percentage in each row. For example:
import arcpy
fc = r'C:pathtoyourfile_geodatabase.gdbfeatureclass'
with arcpy.da.UpdateCursor(fc, ("african_american", "hispanic", "white", "index")) as cursor:
for row in cursor:
max_val = max(row) # Find the max value in each row
max_index = row.index(max_val) # Find the index of the max value
row[3] = max_index + 1 # Apply a correction on the index
cursor.updateRow(row)
answered 2 hours ago
Aaron♦Aaron
37.9k19109253
add a comment |
I prefer to use an arcpy UpdateCursor for tasks such as these, mainly because I think the syntax is easier to work with and can be incorporated into larger workflows.
In your case, find the index of the largest percentage in each row. For example:
import arcpy
fc = r'C:pathtoyourfile_geodatabase.gdbfeatureclass'
with arcpy.da.UpdateCursor(fc, ("african_american", "hispanic", "white", "index")) as cursor:
for row in cursor:
max_val = max(row) # Find the max value in each row
max_index = row.index(max_val) # Find the index of the max value
row[3] = max_index + 1 # Apply a correction on the index
cursor.updateRow(row)
answered 2 hours ago
Aaron♦Aaron
37.9k19109253
I prefer to use an arcpy UpdateCursor for tasks such as these, mainly because I think the syntax is easier to work with and can be incorporated into larger workflows.
In your case, find the index of the largest percentage in each row. For example:
import arcpy
fc = r'C:pathtoyourfile_geodatabase.gdbfeatureclass'
with arcpy.da.UpdateCursor(fc, ("african_american", "hispanic", "white", "index")) as cursor:
for row in cursor:
max_val = max(row) # Find the max value in each row
max_index = row.index(max_val) # Find the index of the max value
row[3] = max_index + 1 # Apply a correction on the index
cursor.updateRow(row)
answered 2 hours ago
Aaron♦Aaron
37.9k19109253
answered 2 hours ago
Aaron♦Aaron
37.9k19109253
answered 2 hours ago
Aaron♦Aaron
37.9k19109253
answered 2 hours ago
Aaron♦Aaron
37.9k19109253
37.9k19109253
add a comment |
add a comment |
John is a new contributor. Be nice, and check out our Code of Conduct.
John is a new contributor. Be nice, and check out our Code of Conduct.
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Welcome to GIS SE! We're a little different from other sites; this isn't a discussion forum but a Q&A site. Please check out our short tour to learn about our focussed Q&A format. Please always present any code using formatted text (highlight it use the {} button) rather than pictures.
– PolyGeo♦
2 hours ago