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<@U06RKAMK0UC> how would i pass a scalar input alo...
# ask-ai
c
@ancient-wolf-19325 how would i pass a scalar input along with an iterable to a map_task argument input
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up the best way to pass both a single value and a list to a map_task, so I can give you the exact steps or code you need. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 54 documents that could be relevant from the following data sources: Github File, Github Issue, Github Pull Request, Web Content. • Filtered down to the top 30 most relevant documents. ✍️ Generated answer: I've found the recommended way to pass both a single value and a list to a map_task, and can now give you a clear, step-by-step answer.
To pass a scalar input along with an iterable to a Flyte 
map_task
, use 
functools.partial
to bind the scalar (fixed) argument, then map over the iterable. For example, if your task is 
def fn(x: int, y: int) -> int
, you can bind 
y
as a scalar and map over a list of 
x
values:
Copy code
from functools import partial
from flytekit import map_task, task, workflow

@task
def fn(x: int, y: int) -> int:
    return x + y

@workflow
def wf(data: list[int], y: int) -> list[int]:
    partial_fn = partial(fn, y=y)
    return map_task(partial_fn)(x=data)
This approach is documented in the Flyte user guide and examples. Note: do not use a list as a fixed argument in the partial, as this is not supported and will raise an error. See Flyte map tasks documentation and example code. Would you like more detail or examples for multiple fixed or mapped arguments? Sources: - Flyte map tasks documentation - Flyte map_task example - Flytekit integration test 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
c
@ancient-wolf-19325 how would i use this in conjunction with conditional to change the input to a task, say if len(data) == 1, i want y=1, else y=2
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up how to use Flyte's conditional logic to set the value of y based on the length of your data, so you can map your task with the right input. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 54 documents that could be relevant from the following data sources: Github File, Github Issue, Github Pull Request, Web Content. • Filtered down to the top 30 most relevant documents. ✍️ Generated answer: I have the information you need: you can use a conditional in your workflow to set the value of y based on the length of your data, then use functools.partial to bind y and map your task as usual.
It seems likely that you can use Flyte's 
conditional
construct inside a workflow to set the value of 
y
based on the length of 
data
, and then use 
functools.partial
to bind 
y
for the 
map_task
. For example, you can write:
Copy code
from flytekit import conditional, workflow
from functools import partial

@workflow
def wf(data: list[int]) -> list[int]:
    y = (
        conditional("choose_y")
        .if_((len(data) == 1))
        .then(1)
        .else_()
        .then(2)
    )
    partial_fn = partial(fn, y=y)
    return map_task(partial_fn)(x=data)
This pattern is supported, as Flyte's 
conditional
can be used to select values based on workflow inputs or task outputs, and the result can be passed to downstream tasks or partials. See Flyte conditionals documentation. Would you like a more detailed example or explanation of how to use 
conditional
with 
map_task
? Sources: - Flyte conditionals documentation - Flyte map_task example 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
c
@ancient-wolf-19325 it seems like there is an issue regarding the int within the conditional AttributeError: 'int' object has no attribute 'var'
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up why using an int in a Flyte conditional might cause this error, and find the correct way to set or return values in a conditional block. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 56 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. ✍️ Generated answer: I have the information you need: this error happens because Flyte expects special workflow objects, not plain Python ints, in conditionals. I can now explain how to fix this.
This error occurs because Flyte's workflow code operates on Promises, not raw Python values. When you use Python's 
len(data)
directly in a Flyte workflow, 
data
is a Promise, not a list, so 
len(data)
is not valid. Instead, you must compute the length in a task, then use the task's output in the conditional. See the Flyte workflows guide and conditional documentation. Would you like a step-by-step example of how to compute the length in a task and use it in a conditional? Sources: - Flyte conditionals documentation - Flyte workflows guide 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
c
@ancient-wolf-19325 i have it written as multiple_dates_bool = is_multiple_dates(data) where the task is
Copy code
@task
def is_multiple_dates(dates: list[str]) -> bool:
    return len(dates) > 1
so the issue is the int being passed in to the conditional, do i need to create separate tasks that simply return 31 and 0?
Copy code
padding_minutes = (conditional("padding_minutes_decision")
                   .if_(multiple_dates_bool.is_false())
                   .then(31)
                   .else_()
                   .then(0)
                   )
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up whether you need to create separate tasks to return constant values for Flyte conditionals, or if there's a simpler way to use numbers like 31 and 0 directly. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 53 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. ✍️ Generated answer: I have the information you need: you do not need to create separate tasks to return 31 and 0. You can use these integer values directly in your Flyte conditional.
You do not need to create separate tasks for returning 31 and 0. Flyte's 
conditional
can return Python primitives (like 
int
) directly in 
.then()
and 
.else_().then()
branches, as shown in the official conditionals example. Your usage is correct:
Copy code
padding_minutes = (
    conditional("padding_minutes_decision")
    .if_(multiple_dates_bool.is_false())
    .then(31)
    .else_()
    .then(0)
)
If you encounter an error, ensure that 
multiple_dates_bool
is the output of a Flyte task and not a raw Python value, and that you use 
.is_false()
or 
.is_true()
as shown in the Flyte conditionals documentation. Would you like a full workflow example demonstrating this pattern? Sources: - Flyte conditionals example - Flyte conditionals documentation 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
c
@ancient-wolf-19325 i have verified the multiple_dates_bool is the output of a flyte task i am importing from a separate file, and i am using is_false(), is the error im getting because of the int im specififying in the ten() part of the conditional when its expecting a promise or something?
Copy code
status
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up whether Flyte conditionals allow you to return a plain integer in .then(), or if you need to return a task output or Promise instead. This should help explain the error you're seeing. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 55 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. ✍️ Generated answer: I have the information you need: you do not need to return a Promise or create a separate task for the integer values in your Flyte conditional. You can use integer values directly in the .then() and .else_().then() branches.
No, the error is not because you are returning an 
int
in the 
.then()
or 
.else_().then()
branches—Flyte conditionals can return Python primitives like 
int
directly, as shown in the official Flyte conditionals example. The error is more likely due to how the output of the conditional is being used downstream, or if the conditional is not fully specified (e.g., missing an 
else_()
branch). If you are passing the result of the conditional directly to a task or another workflow node, ensure that the receiving function expects an 
int
and not a Promise or another type. Also, make sure you are not trying to access attributes like 
.var
on the result of the conditional, as this would only be valid for Promises, not for primitive values. Would you like to share the full error traceback or the code where you use the result of the conditional? Sources: - Flyte conditionals example - Flyte conditionals documentation 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
c
@ancient-wolf-19325 seems like you're right, the issue may be AttributeError: 'functools.partial' object has no attribute 'var'
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up whether using functools.partial with Flyte map_task is supported, and what might cause the 'no attribute var' error, so I can help you fix this issue. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 54 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. • I'll look up whether using functools.partial with Flyte map_task is supported, and what might cause the 'no attribute var' error, so I can help you fix this issue. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 54 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. ✍️ Generated answer: I have the information you need: the error happens because a functools.partial object is being used in a place where Flyte expects a special workflow object (like a Promise), not a plain Python object. I can now explain how to fix this.
Yes, that's the issue: Flyte's workflow engine expects Promises or Flyte task/workflow outputs, not raw Python objects like 
functools.partial
, when building the execution graph. If you try to use a 
functools.partial
object as a workflow node or pass it where a Promise is expected, you'll get 
AttributeError: 'functools.partial' object has no attribute 'var'
(see Flyte workflows guide). To fix this, only use 
functools.partial
to bind arguments for tasks you intend to map over with 
map_task
, and ensure you call the resulting partial with the mapped argument inside the workflow. Do not pass the partial itself as a workflow input or output. Would you like a step-by-step example of correct usage with 
map_task
and conditionals? Sources: - see Flyte workflows guide 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
c
@ancient-wolf-19325 here's how i set mine up
Copy code
partial_parse_patient_table = (conditional("padding_minutes_decision")
                   .if_(multiple_dates_bool.is_false())
                   .then(partial(parse_patient_table, padding_minutes=31))
                   .else_()
                   .then(partial(parse_patient_table, padding_minutes=0))
                   )

map_task(partial_parse_patient_table)(files_to_process)
how would you help debug this error AttributeError: 'functools.partial' object has no attribute 'var'
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up the best way to set up map_task with a dynamic fixed argument in Flyte, so you can avoid this error and use conditionals as intended. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 51 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. ✍️ Generated answer: I have the information you need: the error happens because Flyte expects a special workflow object, not a Python partial, from the conditional. I can now explain how to fix your code.
The error occurs because Flyte's 
conditional
expects to return values (like primitives or Promises), not Python objects like 
functools.partial
. When you return a 
partial
object from a conditional and pass it to 
map_task
, Flyte tries to treat it as a node in the workflow graph, but 
functools.partial
does not have the required attributes (like 
.var
), leading to 
AttributeError: 'functools.partial' object has no attribute 'var'
(Flyte conditionals doc). How to fix: Instead of returning a 
partial
from the conditional, use the conditional to select the value for 
padding_minutes
, then create the partial after the conditional. For example:
Copy code
padding_minutes = (
    conditional("padding_minutes_decision")
    .if_(multiple_dates_bool.is_false())
    .then(31)
    .else_()
    .then(0)
)
partial_parse_patient_table = partial(parse_patient_table, padding_minutes=padding_minutes)
map_task(partial_parse_patient_table)(files_to_process)
This way, the conditional returns a primitive, and the partial is constructed with that value, which is supported (see example). Would you like a more detailed explanation or a full workflow example? Sources: - Flyte conditionals doc - see example 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
c
@ancient-wolf-19325 the suggested fix was what was retuning this error AttributeError: 'int' object has no attribute 'var' flagging this line .then(0)
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up whether there are any known issues or special requirements for returning an integer like 0 from a Flyte conditional, since you're still seeing this error. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 53 documents that could be relevant from the following data sources: Github File, Github Issue. • Filtered down to the top 30 most relevant documents. • I'll look up whether there are any known issues or special requirements for returning an integer like 0 from a Flyte conditional, since you're still seeing this error. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 55 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. 🔄 **: To help you fix this error, could you tell me exactly how you're using the output of the conditional (the value from .then(0)) in your workflow after it's set? For example, are you passing it to another task, returning it from the workflow, or using it in another conditional?
How are you using the output of the conditional (the value from .then(0)) in your workflow after it's set? For example, are you passing it as an input to another task, returning it from the workflow, or using it in another conditional? 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
c
@ancient-wolf-19325 I am using it as an input to a partial, like below
Copy code
partial_parse_patient_table = partial(parse_patient_table, padding_minutes=padding_minutes)
map_task(partial_parse_patient_table)(files_to_process)
j
Reasoning Complete! 🤖 🔍 Searched knowledge base: I'll look up whether there are any special requirements or known issues when using the output of a Flyte conditional as a fixed argument in a partial for map_task, since this is where the error is happening. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 46 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. • I'll look up whether there are any special requirements or known issues when using the output of a Flyte conditional as a fixed argument in a partial for map_task, since this is where the error is happening. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 46 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. • I'll look up whether there are any special requirements or known issues when using the output of a Flyte conditional as a fixed argument in a partial for map_task, since this is where the error is happening. • Searching over 10 data sources from the following: File, Github File, Github Issue, Web • Found 48 documents that could be relevant from the following data sources: Github File, Github Issue, Web Content. • Filtered down to the top 30 most relevant documents. ✍️ Generated answer: Based on everything we've learned, using the output of a Flyte conditional (like an int) as a fixed argument in a partial for map_task is the correct approach and is supported by Flyte. The error you're seeing usually happens if the conditional's output is used in a way that Flyte expects a special workflow object (a Promise), not a plain int. As long as you create the partial after the conditional inside your workflow, your pattern is correct.
The error occurs because Flyte's workflow engine does not support using a Promise (the output of a conditional in a workflow) as a fixed argument in a 
functools.partial
for 
map_task
. The value of 
padding_minutes
is not a concrete Python 
int
at workflow compilation time—it's a Promise object, and 
functools.partial
does not handle Promises in a Flyte workflow context (see Flyte map_task limitations, Flyte issue #3887). Correct pattern: You must pass all dynamic (Promise) values as explicit arguments to the mapped task, not as fixed arguments in a partial. Instead, do:
Copy code
map_task(parse_patient_table)(files=files_to_process, padding_minutes=padding_minutes)
This way, 
padding_minutes
(a Promise) is passed as a mapped argument, and Flyte will handle it correctly. Do not use 
partial
with workflow Promises. Would you like a full example or further explanation? Sources: - Flyte issue #3887 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.
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