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In the Data Grid, you can review how the current recipe applies to the individual columns in your sample. The grid is available through the Transformer page.
- Click column headings to review suggestions for transforms to apply to the column.
Select specific values in a column for suggestions on those strings.
NOTE: Values in a cell cannot exceed 25,000 characters in length.
Tip: If you select a single value in the data grid, the transform cards suggest operations specific to that string. If you multi-select multiple values, the suggestions can apply any pattern shared between the values. For example, selecting "
, CA" and "
, NY" results in suggestions for how to handle state abbreviations in a column.
- When you select a column, you can preview a set of transform cards or a suggested recipe step to edit. These appear at the bottom of the page.
- Suggestions are also generated when you select one or more values in the data histogram for a column or individual values in the displayed rows of the sample.
- See Transform Cards Panel.
- Use the scroll bar to the right of the displayed rows of data to show other rows in the sample. To review rows of the sample data that are not displayed, you may click values in a column and then scroll down through the sampled data.
- Use horizontal scrolling to review additional columns that are off-screen.
Tip: If the contents of a cell are too large for the display, you can click the Caret ( > ) icon to the right of the cell value in the data grid to display the entire contents of the cell.
- To review the recipe in development, open the Recipe panel on the right side of the screen. See Recipe Panel.
- You can modify a recipe step selected in the panel. See Transform Builder.
- To review details about an individual column, select Column Details from the column drop-down. See Column Details Panel.
- To review details about a selection of columns, open the left panel. See Column Browser Panel.
Above the Data Grid, you can review summary information about the data in your currently selected sample.
Tip: Before you begin transforming your data, you might want to verify the columns and count of data types against the data before it was imported. If there are discrepancies, you might want to investigate the differences. Unless your sample includes the entire dataset, row counts should differ.
NOTE: In the Photon running environment, results can differ between executions of the same recipe due to Photon's parallel execution and data limiting within the Transformer page. In particular, joins with multiple matches per key can sometimes cause a difference in the number of reported rows when the job is re-executed.
- To review and analyze across multiple columns, click Columns. See Column Browser Panel.
- To return to the data grid, click Grid.
- To review the samples for the loaded dataset, click the dataset link. See Sampling Menu.
Click the data types link to review the data type for each column. See Supported Data Types.
Filter: Enter text to begin filtering the rows for display in the data grid.
Tip: When you are previewing a recipe step, click the Transformed link to display in the data grid only the rows that have been modified by the currently configured recipe.
Data Grid Options
Use the right-hand menu to toggle display of various features in the Transformer page:
- Preview: Toggle display of previews of changes. For large datasets containing dozens of columns, disabling previews can improve performance.
Show Whitespace: When enabled, non-visible characters such as spaces, new lines, and tabs appear in the data as pink icons.
NOTE: If you are using imported datasets with fixed-width columns, you should disable the Show Whitespace option. These columns can conflict with the platform's ability to compute a cell's whitespace, which can impact performance and can cause the browser to crash.
- Card Suggestions: Toggle display of the transform cards, which can be used for quickly applying transform steps on individual columns. Cards are only displayed if a suggestion for your current selection is available.
- Show Wrangle Script: Toggle display of recipe steps in either natural, readable language or in native Wrangle (a domain-specific language for data transformation).
At the top of the column, you can review:
- the data type and name of the column
- the data quality bar
- the data histogram that summarizes the range of values in the sampled column.
Tip: These values represent counts of the displayed sample.
The contents of the column histogram vary depending on the data type for the column. For example, columns of Integer type display the range of integers, while columns of String type cover the frequency of individual string values in the column.
Tip: If you hover over a bar in the histogram, you can review specific values, the count of that value, and the percentage that value represents of the total count of values in the column.
For more information, see Column Menus.
You can click and drag to select values in a column:
- Select a single value in the column to prompt a set of suggestions at the bottom of the screen.
- Select multiple values in a single cell to receive a different set of suggestions.
- You can select individual values in the column histogram or categories of values in the data quality bar, prompting a set of suggestions.
- See Transform Cards Panel.
- Double-click performs word selection, and triple-click selects an entire cell value.
- When you select values, some values in other columns are highlighted in a darker color, which provides some indication of correlation between values.
Data quality bar
Just below the column name is a horizontal band, which identifies data quality issues among the sample values in the column. Each color band identifies the relative number of records that fit the following data quality definitions:
|Red||A value that does not match the listed data type. For example, if a column of Zip type contains, |
|Black||No value is present. Missing values may or may not generate errors in the target application.|
You can use a column's data quality bar to build a recipe step to address selected data. For example, click the red set of values in the data quality bar to generate a set of transform cards or the beginning of a step in the Transform Editor to address mismatched values in the column.
Tip: The histogram may also show you unwanted variation in your values. For example, if the column stores latitude data, the precision may be too fine (e.g.
37.76). You can use recipe steps to round your data to a more usable level of precision and thereby reduce the number of unique values in the column to a more manageable count. See ROUND Function.
Below the data quality bar, a column histogram displays the count of each detected value in the column (for string data) or the count of values within a numeric range (for number data). You can use this histogram to identify unusual values or outlier values, which should be removed or correct.
- Select one or more values in the histogram to prompt a set of suggestions for addressing the data.
CTRL- click to select multiple values.
Individual bars in a histogram for a numeric column often represent a range of values. Some notes:
- For a numeric range bar that overlaps values in another bar, values are inclusive on the lower bound and exclusive on the upper bound. For example, if a histogram bar represents the values 0-10, it includes the count of instances of 0 and does not include the count of instances of 10. The count of instances of 10 is part of the adjacent bar in the histogram.
- The above applies only when there are overlapping values between data ranges. If there are no overlapping values, then the range includes the values of the lower and upper boundaries.
Tip: When you resize the width of a column, the number of bars displayed in the column histogram changes accordingly. You can use this dynamic resizing to change the granularity displayed in histograms.
On the left side of the screen, you can see a column of black dots. If you hover over one of these, you can see the current row number and, if the information is still available, the row number for the row from the original source data. These values apply only to the sample in the current dataset.
Tip: To review the original row number for a row, hover over the black dot in the data grid. These values can be referenced using the
SOURCEROWNUMBER function in your recipe steps. Some transform steps, such as
union , may make the original row information invalid or otherwise unavailable, which disables this option. See SOURCEROWNUMBER Function.
Before a transform in development has been added to the recipe, a preview of the results is generated in the data grid. See Transform Preview.
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