topic Re: Repeating Tuples with Insert/Search Cursor in Python Questions

Repeating Tuples with Insert/Search Cursor

KevinDickinson1 — Fri, 26 Dec 2025 22:56:40 GMT

I am trying to use an InsertCursor/SeachCursor to transfer data from one dataset to another wile incorporating a repeating tuple. The first dataset (in the below code is "Forest_Surface_Fuels") contains all the data and has attribute fields for each record that contains data for 1hr, 10hr, and 100hr fuels. What I am trying to do as I transfer this data to a empty dataset ("1_10_100") is to not only take the values in those fields, but create a master list for all records in a project and in a new field state whether the data is a 1hr, 10hr, or 100hr.

Here is the code that I have:

# Fields that data will be inserted into in the final excel table
fields = ['Plot_', 'SurveyType', 'Transect', 'OneHour', 'TenHr', 'HunHr']

#The data to be inserted (this is the tuple that will be repeated)
fuelsTuple = [
('Macroplot', "Pre", "1", 'onehr_pre_1', 'tenhr_pre_1', 'hundhr_pre_1'),
('Macroplot', "Pre", "2", 'onehr_pre_2', 'tenhr_pre_2', 'hundhr_pre_2'),
('Macroplot', "Post", "1", 'onehr_post_1', 'tenhr_post_1', 'hundhr_post_1'),
('Macroplot', "Post", "2", 'onehr_post_2', 'tenhr_post_2', 'hundhr_post_2')
]

#make count of times to repeat the tuple
repeats = arcpy.management.GetCount("Forest_Surface_Fuels")
count = int(repeats[0])

#Insert Cursor to update fields
plotCursor = arcpy.da.InsertCursor("Forest_Surface_Fuels", fuelsTuple)
with arcpy.da.SearchCursor("1_10_100", fields) as cursor:
for i in range(count):
for row in cursor:
plotCursor.insertRow(row)
del plotCursor
del cursor

When I run this, I get this error:

Thanks!

Re: Repeating Tuples with Insert/Search Cursor

VenkataKondepati — Sat, 27 Dec 2025 03:43:06 GMT

You’re very close, but the cursors are flipped and you’re passing the tuple list as “fields” (that’s why it blows up).

SearchCursor should read from Forest_Surface_Fuels (source)
InsertCursor should write to 1_10_100 (target)
InsertCursor("Forest_Surface_Fuels", fuelsTuple) is wrong because the 2nd argument must be a list of field names, not row data.

If your goal is: for each input feature, create 4 rows (Macroplot Pre/Post x Transect 1/2) and pull values from those named fields, do this pattern:

out_fields = ['Plot_', 'SurveyType', 'Transect', 'OneHour', 'TenHr', 'HunHr'] templates = [ ("Pre","1", "onehr_pre_1","tenhr_pre_1","hundhr_pre_1"), ("Pre","2", "onehr_pre_2","tenhr_pre_2","hundhr_pre_2"), ("Post","1","onehr_post_1","tenhr_post_1","hundhr_post_1"), ("Post","2","onehr_post_2","tenhr_post_2","hundhr_post_2"), ] # read Plot_ plus all fuel fields you reference src_fields = ['Plot_'] + sorted({f for t in templates for f in t[2:]}) with arcpy.da.SearchCursor("Forest_Surface_Fuels", src_fields) as sc, \ arcpy.da.InsertCursor("1_10_100", out_fields) as ic: idx = {name:i for i,name in enumerate(src_fields)} for r in sc: plot_id = r[idx['Plot_']] for survey, tran, f1, f10, f100 in templates: ic.insertRow([plot_id, survey, tran, r[idx[f1]], r[idx[f10]], r[idx[f100]]])

That gives you the “master table” (one row per plot per survey/transect) with 1/10/100 hr values populated correctly.

Re: Repeating Tuples with Insert/Search Cursor

KevinDickinson1 — Sun, 28 Dec 2025 16:32:37 GMT

I keep getting an error, but want to confirm something first, when you define src_fields, where you have 'Plot_' that should be the corresponding field in "Forest_Surface_Fuels" to 'Plot_' in the out_fields, correct? I replaced 'Plot_' in those instances with 'Macroplot' and still get this error:

Re: Repeating Tuples with Insert/Search Cursor

HaydenWelch — Tue, 30 Dec 2025 15:16:26 GMT

I'd approach this by making the field tuple a bit more complex. It seems that the first records are raw data and the last few are field values. You can just break it into two mappings like this:

# First Dictionary is direct data writes, second is field values to pull from the Origin dataset conversion_map: list[tuple[dict[str, Any], dict[str, Any]]] = [ ( {'Plot_': 'Macroplot', 'SurveyType': 'Pre', 'Transect': '1'}, {'OneHour': 'onehr_pre_1', 'TenHr': 'tenhr_pre_1', 'HunHr': 'hundhr_pre_1'} ), ( {'Plot_': 'Macroplot', 'SurveyType': 'Pre', 'Transect': '2'}, {'OneHour': 'onehr_pre_2', 'TenHr': 'tenhr_pre_2', 'HunHr': 'hundhr_pre_2'} ), ( {'Plot_': 'Macroplot', 'SurveyType': 'Post', 'Transect':'1'}, {'OneHour': 'onehr_post_1', 'TenHr': 'tenhr_post_1', 'HunHr': 'hundhr_post_1'} ), ( {'Plot_': 'Macroplot', 'SurveyType': 'Post', 'Transect':'2'}, {'OneHour': 'onehr_post_2', 'TenHr': 'tenhr_post_2', 'HunHr': 'hundhr_post_2'} ), ]

That will make it clearer later what the raw data mapping is and what the extracted field values are.

When dealing with multiple cursors, I tend to like mapping the rows instead of using an index. This can be done with this incredibly simple helper function:

def as_dict(cur: SearchCursor) -> Iterator[dict[str, Any]]: for row in cur: yield dict(zip(cur.fields, row))

You can wrap a cursor with this before iterating and you'll get back a dictionary that can be updated

Now we need to implement the mapping:

def convert(origin: str, target: str, fields: list[str], conversion_map: ConversionMap, null_value: Any=None): with ( SearchCursor(origin, fields) as s_cur, InsertCursor(target, fields) as i_cur ): for row in as_dict(s_cur): for fuel_data, fuel_fields in conversion_map: new_row = fuel_data.copy() new_row.update({k: row.get(v, null_value) for k, v in fuel_fields.items()}) i_cur.insertRow([new_row.get(f, null_value) for f in i_cur.fields])

Here we create a context block with two cursors, one to search through the origin table ("Forest_Surface_Fuels") and one to insert into the target table ("1_10_100").

(line: 2) Create a context block with 2 cursors for the Target and Origin
(line: 6) Iterate dictionary mappings of the origin rows
(line: 7) Iterate all defined row conversions
(line: 8 ) Create a copy of the template row data
(line: 9) Get the field value of the current origin row for each mapped target field
(line: 10) Create a row in the correct shape by iterating the insert fields and grabbing the new_row values

The null_value here shouldn't ever trigger, since it'll only exist if the fieldname doesn't exist in the origin table. If you don't have any 0 values, you can re-map nulls by using an or instead:

new_row.update({k: row.get(v) or null_value for k, v in fuel_fields.items()})

This abuses pythons truthiness, so any value that's considered falsey will get the null_value ('', 0, False, None, etc.)

Finally, we need to put all this together into a script that doesn't pollute the global namespace with cursor references. Basically just put your logic into an if __name__ == '__main__' block:

from collections.abc import Iterator from typing import Any from arcpy.da import SearchCursor, InsertCursor ConversionMap = list[tuple[dict[str, Any], dict[str, Any]]] def as_dict(cur: SearchCursor) -> Iterator[dict[str, Any]]: for row in cur: yield dict(zip(cur.fields, row)) def convert(origin: str, target: str, fields: list[str], conversion_map: ConversionMap, null_value: Any=None): with ( SearchCursor(origin, fields) as s_cur, InsertCursor(target, fields) as i_cur ): for row in as_dict(s_cur): for fuel_data, fuel_fields in conversion_map: new_row = fuel_data.copy() new_row.update({k: row.get(v, null_value) for k, v in fuel_fields.items()}) i_cur.insertRow([new_row.get(f, null_value) for f in i_cur.fields]) if __name__ == '__main__': # Fields that data will be inserted into in the final excel table FIELDS = ['Plot_', 'SurveyType', 'Transect', 'OneHour', 'TenHr', 'HunHr'] ORIGIN_DATA = "Forest_Surface_Fuels" TARGET_DATA = "1_10_100" # Update this with the Null Value you want to use, e.g. ['' or -1 or None] NULL_VALUE = None # First Dictionary is direct data writes, second is field values to pull from the Origin dataset CONVERSION_MAP: ConversionMap = [ ( # Direct Data Insertion {'Plot_': 'Macroplot', 'SurveyType': 'Pre', 'Transect': '1'}, # Field Value Map from Origin {'OneHour': 'onehr_pre_1', 'TenHr': 'tenhr_pre_1', 'HunHr': 'hundhr_pre_1'} ), ( {'Plot_': 'Macroplot', 'SurveyType': 'Pre', 'Transect': '2'}, {'OneHour': 'onehr_pre_2', 'TenHr': 'tenhr_pre_2', 'HunHr': 'hundhr_pre_2'} ), ( {'Plot_': 'Macroplot', 'SurveyType': 'Post', 'Transect':'1'}, {'OneHour': 'onehr_post_1', 'TenHr': 'tenhr_post_1', 'HunHr': 'hundhr_post_1'} ), ( {'Plot_': 'Macroplot', 'SurveyType': 'Post', 'Transect':'2'}, {'OneHour': 'onehr_post_2', 'TenHr': 'tenhr_post_2', 'HunHr': 'hundhr_post_2'} ), ] convert(ORIGIN_DATA, TARGET_DATA, FIELDS, CONVERSION_MAP, NULL_VALUE)

Re: Repeating Tuples with Insert/Search Cursor

VenkataKondepati — Tue, 30 Dec 2025 16:23:02 GMT

Yes — src_fields must be the field names in Forest_Surface_Fuels, not a value like "Macroplot". So don’t replace Plot_ with "Macroplot" in src_fields. "Macroplot" should be the value you insert, not a column name.

About the error you’re seeing:

RuntimeError: Invalid SQL syntax [near "PLOT": syntax error]

That usually happens when the target table has a field name that the underlying database treats as problematic (often a reserved word like PLOT, or a name that needs quoting). arcpy.da.InsertCursor builds an INSERT statement under the hood and can choke on that.

What to do:

Confirm the exact field name in the output table (not the alias). If it’s PLOT / Plot / Plot_, verify spelling/case.
Rename the output field to something safe like PlotID (best fix).
Re-run the cursor after renaming.

So: keep src_fields as real source column names, and fix the output field name that’s triggering SQL near PLOT.

Re: Repeating Tuples with Insert/Search Cursor

KevinDickinson1 — Tue, 30 Dec 2025 17:15:36 GMT

I ended up needing to convert Forest_Surface_Fuels to a temporary layer for this to work, but it works as I hoped, so thank you!