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| author | lewuathe <lewuathe@me.com> | 2015-08-19 09:54:03 +0100 |
|---|---|---|
| committer | Sean Owen <sowen@cloudera.com> | 2015-08-19 09:54:03 +0100 |
| commit | ba2a07e2b6c5a39597b64041cd5bf342ef9631f5 (patch) | |
| tree | 6005346fcddd42bfebc5083ec55562427e8ab1b8 /docs/ml-features.md | |
| parent | 865a3df3d578c0442c97d749c81f554b560da406 (diff) | |
| download | spark-ba2a07e2b6c5a39597b64041cd5bf342ef9631f5.tar.gz spark-ba2a07e2b6c5a39597b64041cd5bf342ef9631f5.tar.bz2 spark-ba2a07e2b6c5a39597b64041cd5bf342ef9631f5.zip | |
[SPARK-9977] [DOCS] Update documentation for StringIndexer
By using `StringIndexer`, we can obtain indexed label on new column. So a following estimator should use this new column through pipeline if it wants to use string indexed label.
I think it is better to make it explicit on documentation.
Author: lewuathe <lewuathe@me.com>
Closes #8205 from Lewuathe/SPARK-9977.
Diffstat (limited to 'docs/ml-features.md')
| -rw-r--r-- | docs/ml-features.md | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/docs/ml-features.md b/docs/ml-features.md index d82c85ee75..8d56dc32ca 100644 --- a/docs/ml-features.md +++ b/docs/ml-features.md @@ -725,7 +725,11 @@ dctDf.select("featuresDCT").show(3); `StringIndexer` encodes a string column of labels to a column of label indices. The indices are in `[0, numLabels)`, ordered by label frequencies. So the most frequent label gets index `0`. -If the input column is numeric, we cast it to string and index the string values. +If the input column is numeric, we cast it to string and index the string +values. When downstream pipeline components such as `Estimator` or +`Transformer` make use of this string-indexed label, you must set the input +column of the component to this string-indexed column name. In many cases, +you can set the input column with `setInputCol`. **Examples** |