- Where to find Data Wrangler in the SageMaker console
- How to import a tabular CSV from Amazon S3
- How to inspect schema, distributions, and anomalies
- How to apply transforms (imputation) and review a dataset summary
- How to export a clean dataset for training
Locate Data Wrangler in the SageMaker Console
AWS periodically reorganizes the console UI, so the first step is locating Data Wrangler inside the SageMaker product area.
Data Wrangler Interface — Import and Prepare
Open Data Wrangler to begin a new flow. The UI shows import, prepare, and analyze steps visually so you can build a reproducible data flow.
Import a CSV from Amazon S3
Data Wrangler supports many sources: local uploads,Snowflake, Redshift, PostgreSQL, MySQL, and Amazon S3. For this demo the raw dataset is stored in S3 under a bucket named “Machine Learning Demo”. We navigate to that S3 location and select the Titanic CSV to import.


Survived column is detected as numeric/binary with two classes, 0 and 1. Data Wrangler shows distribution percentages (e.g., ~61.44% class 0, 38.56% class 1) when you hover over categories, which helps assess class balance before modeling.
Apply a Transform — Imputation
Common preprocessing tasks are available as built-in transforms. One frequent action is imputing missing numeric values (replaceNaN with mean, median, etc.).
Imputation replaces missing numeric values using a chosen strategy (mean, median, mode, constant, etc.). The
median is robust to outliers and is often a safe default when numeric distributions are skewed.median strategy and target numeric columns such as Pclass, Fare, and Age. After applying the transform, Data Wrangler runs the step and updates the preview.

Review Data Flow and Dataset Summary
The Data Flow diagram visualizes each node: original source → inferred types → added transforms (imputation, formulas, filters, etc.). This makes your preparation pipeline reproducible and auditable. After running the analysis Data Wrangler produces a dataset summary. For the Titanic demo the summary shows:
Inspect Anomalies and Feature-Level Analysis
Data Wrangler highlights anomalous samples and their anomaly scores so you can review outliers, data quality issues, or edge cases that may affect modeling.
Survived) you can drill down to view:
- Histograms and distributions
- Validity and missing-value percentages
- Value counts or percentiles for numeric columns

Quick Step-by-Step Summary
- Open SageMaker Canvas / Studio and launch Data Wrangler.
- Import your dataset (e.g., CSV from
Amazon S3). - Inspect inferred schema, distributions, and missing values.
- Add transforms (imputation, encoding, normalization, custom formulas).
- Run the flow and review the dataset summary and anomaly table.
- Export the cleaned dataset to your training pipeline or notebook.
Common Data Sources (examples)
Links and References
- Amazon Kinesis — real-time data streaming (for streaming ingestion pipelines)
- Amazon SageMaker Data Wrangler — product page
- SageMaker Studio documentation
- SageMaker Canvas
- Amazon S3 documentation