# DynamicFrameCollection class A `DynamicFrameCollection` is a dictionary of [DynamicFrame class](aws-glue-api-crawler-pyspark-extensions-dynamic-frame.md) objects, in which the keys are the names of the `DynamicFrames` and the values are the `DynamicFrame` objects. ## \$1\$1init\$1\$1 **`__init__(dynamic_frames, glue_ctx)`** + `dynamic_frames` – A dictionary of [DynamicFrame class](aws-glue-api-crawler-pyspark-extensions-dynamic-frame.md) objects. + `glue_ctx` – A [GlueContext class](aws-glue-api-crawler-pyspark-extensions-glue-context.md) object. ## Keys `keys( )` – Returns a list of the keys in this collection, which generally consists of the names of the corresponding `DynamicFrame` values. ## Values `values(key)` – Returns a list of the `DynamicFrame` values in this collection. ## Select **`select(key)`** Returns the `DynamicFrame` that corresponds to the specfied key (which is generally the name of the `DynamicFrame`). + `key` – A key in the `DynamicFrameCollection`, which usually represents the name of a `DynamicFrame`. ## Map **`map(callable, transformation_ctx="")`** Uses a passed-in function to create and return a new `DynamicFrameCollection` based on the `DynamicFrames` in this collection. + `callable` – A function that takes a `DynamicFrame` and the specified transformation context as parameters and returns a `DynamicFrame`. + `transformation_ctx` – A transformation context to be used by the callable (optional). ## Flatmap **`flatmap(f, transformation_ctx="")`** Uses a passed-in function to create and return a new `DynamicFrameCollection` based on the `DynamicFrames` in this collection. + `f` – A function that takes a `DynamicFrame` as a parameter and returns a `DynamicFrame` or `DynamicFrameCollection`. + `transformation_ctx` – A transformation context to be used by the function (optional).