Perform some basic queries

Perform some basic queries#

A core functionality of ancpBIDS is to extract information from datasets. With the layout now held in-memory, we can use several built-in functions to extract useful information from the dataset; for example, accesing common entities such as Subjects, Tasks, and Runs. These simple queries are build in as ´layout.get_”NameOfTheEntity”()´. If the entity does not exist in the dataset or the name is not properly written, the query will return an empty list ´[]´.

  • Get all subjects in the dataset

subs = layout.get_subjects()
print(subs)

# Output: 
#['009', '012', '013', '014', '015', '016', '017', '018', '019', '020', '021', '022', '023', '024', '025', '026', '027', '028', '029', '030', '031']

subs=layout.get_subjects()
print(subs)

#Output:
# ['01', '02', '03', '04', '05', '06', '07', '08', '09', '10', '11', '12', '13', '14', '15', '16']

  • Find how many runs there are

runs=layout.get_runs()
print(runs)
#Output
#['1']

sruns=layout.get_runs()
print(runs)
#Output:
#['01', '02', '03']

Note that the returned runs are collected over all subjects and it is not guaranteed that each participant has the same number of runs.

  • Check out the tasks of the experiment

tasks = layout.get_tasks()
print(tasks)

#Output:
#['deduction','induction']

task = layout.get_task()
print(task)

#Output:
#['mixedgamblestask']

Query entities#

If you want to check which entities exist in your dataset, you can use the following function to receive a dictionary with all entities in the dataset and its respective values.

avail_entitities=layout.get_entities()
print("Entities: ", list(avail_entitities.keys()))
print("Value of task: ", avail_entitities['task'])

#Output:
#Entities:  ['sub', 'ses', 'task', 'run', 'desc']
#Value of task:  {'deduction', 'induction'}

avail_entitities=layout.get_entities()
print("Entities: ", list(avail_entitities.keys()))
print("Value of task: ", avail_entitities['task'])

#Output:
#Entities:  ['task', 'sub', 'run', 'ds', 'type']
#Value of task:  {'mixedgamblestask'}

Next Section#

In the next section we will continue with more advanced queries using multiple filtering parameters and specific BIDS Key-value pairs.

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