本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。 # FlatMap 類別將轉換套用至集合中的各個 `DynamicFrame`。結果不會扁平化為單一的 `DynamicFrame`，而是保留為集合。 ## FlatMap 的範例下列範例程式碼片段示範如何在套用至 `FlatMap` 時對動態影格集合使用 `ResolveChoice` 轉換。用於輸入的資料位於 Amazon S3 地址 `s3://bucket/path-for-data/sample.json` 預留位置的 JSON 中，並包含下列資料。 ### 範例 JSON 資料 ``` [{ "firstname": "Arnav", "lastname": "Desai", "address": { "street": "6 Anyroad Avenue", "city": "London", "state": "England", "country": "UK" }, "phone": 17235550101, "affiliations": [ "General Anonymous Example Products", "Example Independent Research", "Government Department of Examples" ] }, { "firstname": "Mary", "lastname": "Major", "address": { "street": "7821 Spot Place", "city": "Centerville", "state": "OK", "country": "US" }, "phone": 19185550023, "affiliations": [ "Example Dot Com", "Example Independent Research", "Example.io" ] }, { "firstname": "Paulo", "lastname": "Santos", "address": { "street": "123 Maple Street", "city": "London", "state": "Ontario", "country": "CA" }, "phone": 12175550181, "affiliations": [ "General Anonymous Example Products", "Example Dot Com" ] }] ``` **Example 將 ResolveChoice 套用至 DynamicFrameCollection 並顯示輸出。** ``` #Read DynamicFrame datasource = glueContext.create_dynamic_frame_from_options("s3", connection_options = {"paths":["s3://bucket/path/to/file/mysamplejson.json"]}, format="json") datasource.printSchema() datasource.show() ## Split to create a DynamicFrameCollection split_frame=datasource.split_fields(["firstname","lastname","address"],"personal_info","business_info") split_frame.keys() print("---") ## Use FlatMap to run ResolveChoice kwargs = {"choice": "cast:string"} flat = FlatMap.apply(split_frame, ResolveChoice, frame_name="frame", transformation_ctx='tcx', **kwargs) flat.keys() ##Select one of the DynamicFrames personal_info = flat.select("personal_info") personal_info.printSchema() personal_info.show() print("---") business_info = flat.select("business_info") business_info.printSchema() business_info.show() ``` 呼叫 `FlatMap.apply` 時，`frame_name` 參數**必須**是 `"frame"`。目前不接受其他值。 ### 範例輸出 ``` root |-- firstname: string |-- lastname: string |-- address: struct | |-- street: string | |-- city: string | |-- state: string | |-- country: string |-- phone: long |-- affiliations: array | |-- element: string --- { "firstname": "Mary", "lastname": "Major", "address": { "street": "7821 Spot Place", "city": "Centerville", "state": "OK", "country": "US" }, "phone": 19185550023, "affiliations": [ "Example Dot Com", "Example Independent Research", "Example.io" ] } { "firstname": "Paulo", "lastname": "Santos", "address": { "street": "123 Maple Street", "city": "London", "state": "Ontario", "country": "CA" }, "phone": 12175550181, "affiliations": [ "General Anonymous Example Products", "Example Dot Com" ] } --- root |-- firstname: string |-- lastname: string |-- address: struct | |-- street: string | |-- city: string | |-- state: string | |-- country: string { "firstname": "Mary", "lastname": "Major", "address": { "street": "7821 Spot Place", "city": "Centerville", "state": "OK", "country": "US" } } { "firstname": "Paulo", "lastname": "Santos", "address": { "street": "123 Maple Street", "city": "London", "state": "Ontario", "country": "CA" } } --- root |-- phone: long |-- affiliations: array | |-- element: string { "phone": 19185550023, "affiliations": [ "Example Dot Com", "Example Independent Research", "Example.io" ] } { "phone": 12175550181, "affiliations": [ "General Anonymous Example Products", "Example Dot Com" ] } ``` ## 方法 + [\$1\$1call\$1\$1](#aws-glue-api-crawler-pyspark-transforms-flat-map-__call__) + [套用](#aws-glue-api-crawler-pyspark-transforms-flat-map-apply) + [名稱](#aws-glue-api-crawler-pyspark-transforms-flat-map-name) + [describeArgs](#aws-glue-api-crawler-pyspark-transforms-flat-map-describeArgs) + [describeReturn](#aws-glue-api-crawler-pyspark-transforms-flat-map-describeReturn) + [describeTransform](#aws-glue-api-crawler-pyspark-transforms-flat-map-describeTransform) + [describeErrors](#aws-glue-api-crawler-pyspark-transforms-flat-map-describeErrors) + [描述](#aws-glue-api-crawler-pyspark-transforms-flat-map-describe) ## \$1\$1call\$1\$1(dfc, BaseTransform, frame\$1name, transformation\$1ctx = "", \$1\$1base\$1kwargs) 對集合中的每個 `DynamicFrame` 套用轉換，並將結果扁平化。 + `dfc` – 要對其套用 flatmap 的 `DynamicFrameCollection` (必要)。 + `BaseTransform` – 從 `GlueTransform` 衍生的轉換功能，要套用到集合中的每個成員 (必要)， + `frame_name` – 做為集合元素傳遞目標的引數名稱 (必要)。 + `transformation_ctx` – 用於識別狀態資訊的唯一字串 (選用)。 + `base_kwargs` – 要傳遞到基本轉換的引數 (必要)。傳回新的 `DynamicFrameCollection`，也就是對來源 `DynamicFrameCollection` 中個別 `DynamicFrame` 所套用轉換後所產生的集合。 ## apply(cls, \$1args, \$1\$1kwargs) 繼承自 `GlueTransform` [apply](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-apply)。 ## name(cls) 繼承自 `GlueTransform` [name](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-name)。 ## describeArgs(cls) 繼承自 `GlueTransform` [describeArgs](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describeArgs)。 ## describeReturn(cls) 繼承自 `GlueTransform` [describeReturn](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describeReturn)。 ## describeTransform(cls) 繼承自 `GlueTransform` [describeTransform](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describeTransform)。 ## describeErrors(cls) 繼承自 `GlueTransform` [describeErrors](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describeErrors)。 ## describe(cls) 繼承自 `GlueTransform` [describe](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describe)。