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# SelectFromCollection 類別
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection"></a>

在 `DynamicFrameCollection` 中選擇一個 `DynamicFrame`。

## 範例
<a name="pyspark-SelectFromCollection-example"></a>

此範例使用 `SelectFromCollection` 從 `DynamicFrameCollection` 中選取 `DynamicFrame`。

**範例資料集**

該範例從稱為 `split_rows_collection` 的 `DynamicFrameCollection` 中選取兩個 `DynamicFrames`。以下是 `split_rows_collection` 中的索引鍵清單。

```
dict_keys(['high', 'low'])
```

**範例程式碼**

```
# Example: Use SelectFromCollection to select
# DynamicFrames from a DynamicFrameCollection

from pyspark.context import SparkContext
from awsglue.context import GlueContext
from awsglue.transforms import SelectFromCollection

# Create GlueContext
sc = SparkContext.getOrCreate()
glueContext = GlueContext(sc)

# Select frames and inspect entries
frame_low = SelectFromCollection.apply(dfc=split_rows_collection, key="low")
frame_low.toDF().show()

frame_high = SelectFromCollection.apply(dfc=split_rows_collection, key="high")
frame_high.toDF().show()
```

### Output
<a name="SelectFromCollection-example-output"></a>

```
+---+-----+------------------------+-------------------------+
| id|index|contact_details.val.type|contact_details.val.value|
+---+-----+------------------------+-------------------------+
|  1|    0|                     fax|             202-225-3307|
|  1|    1|                   phone|             202-225-5731|
|  2|    0|                     fax|             202-225-3307|
|  2|    1|                   phone|             202-225-5731|
|  3|    0|                     fax|             202-225-3307|
|  3|    1|                   phone|             202-225-5731|
|  4|    0|                     fax|             202-225-3307|
|  4|    1|                   phone|             202-225-5731|
|  5|    0|                     fax|             202-225-3307|
|  5|    1|                   phone|             202-225-5731|
|  6|    0|                     fax|             202-225-3307|
|  6|    1|                   phone|             202-225-5731|
|  7|    0|                     fax|             202-225-3307|
|  7|    1|                   phone|             202-225-5731|
|  8|    0|                     fax|             202-225-3307|
|  8|    1|                   phone|             202-225-5731|
|  9|    0|                     fax|             202-225-3307|
|  9|    1|                   phone|             202-225-5731|
| 10|    0|                     fax|             202-225-6328|
| 10|    1|                   phone|             202-225-4576|
+---+-----+------------------------+-------------------------+
only showing top 20 rows

+---+-----+------------------------+-------------------------+
| id|index|contact_details.val.type|contact_details.val.value|
+---+-----+------------------------+-------------------------+
| 11|    0|                     fax|             202-225-6328|
| 11|    1|                   phone|             202-225-4576|
| 11|    2|                 twitter|           RepTrentFranks|
| 12|    0|                     fax|             202-225-6328|
| 12|    1|                   phone|             202-225-4576|
| 12|    2|                 twitter|           RepTrentFranks|
| 13|    0|                     fax|             202-225-6328|
| 13|    1|                   phone|             202-225-4576|
| 13|    2|                 twitter|           RepTrentFranks|
| 14|    0|                     fax|             202-225-6328|
| 14|    1|                   phone|             202-225-4576|
| 14|    2|                 twitter|           RepTrentFranks|
| 15|    0|                     fax|             202-225-6328|
| 15|    1|                   phone|             202-225-4576|
| 15|    2|                 twitter|           RepTrentFranks|
| 16|    0|                     fax|             202-225-6328|
| 16|    1|                   phone|             202-225-4576|
| 16|    2|                 twitter|           RepTrentFranks|
| 17|    0|                     fax|             202-225-6328|
| 17|    1|                   phone|             202-225-4576|
+---+-----+------------------------+-------------------------+
only showing top 20 rows
```

## 方法
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-_methods"></a>
+ [\$1\$1call\$1\$1](#aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-__call__)
+ [apply](#aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-apply)
+ [name](#aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-name)
+ [describeArgs](#aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describeArgs)
+ [describeReturn](#aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describeReturn)
+ [describeTransform](#aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describeTransform)
+ [describeErrors](#aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describeErrors)
+ [describe](#aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describe)

## \$1\$1call\$1\$1(dfc, key, transformation\$1ctx = "")
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-__call__"></a>

從 `DynamicFrameCollection` 取得一個 `DynamicFrame`。
+ `dfc` – 應該從其中選取 `DynamicFrame` 的 `DynamicFrameCollection` (必要)。
+ `key` – 所要選擇的 `DynamicFrame` 金鑰 (必要)。
+ `transformation_ctx` – 用於識別狀態資訊的唯一字串 (選用)。

## apply(cls, \$1args, \$1\$1kwargs)
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-apply"></a>

繼承自 `GlueTransform` [apply](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-apply)。

## name(cls)
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-name"></a>

繼承自 `GlueTransform` [name](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-name)。

## describeArgs(cls)
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describeArgs"></a>

繼承自 `GlueTransform` [describeArgs](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describeArgs)。

## describeReturn(cls)
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describeReturn"></a>

繼承自 `GlueTransform` [describeReturn](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describeReturn)。

## describeTransform(cls)
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describeTransform"></a>

繼承自 `GlueTransform` [describeTransform](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describeTransform)。

## describeErrors(cls)
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describeErrors"></a>

繼承自 `GlueTransform` [describeErrors](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describeErrors)。

## describe(cls)
<a name="aws-glue-api-crawler-pyspark-transforms-SelectFromCollection-describe"></a>

繼承自 `GlueTransform` [describe](aws-glue-api-crawler-pyspark-transforms-GlueTransform.md#aws-glue-api-crawler-pyspark-transforms-GlueTransform-describe)。