provides multiple mechanisms for reviewing your column values and identifying patterns in the data format or similar values which mean the same thing. Through simple visual tools, you can select the patterns or clustered value to standardize and, when prompted, the patterns or values to use as their standard. As needed, you can apply formatting or structuring functions to the data for finer grain controls. This section summarizes the available methods of standardization, as well as their recommended uses.
You can use any of the following methods for standardizing values in your dataset's columns. Depending on the situation, you may choose to mix-and-match these methods. Details on these methods are below.
|Method||Description||Recommended Uses||How to Use|
can identify similar values using one of the available algorithms for comparing values. You can compare values based on spelling or language-independent pronunciation.
Available through the Standardize Page
can identify common patterns in a set of values and suggest transformations to standardize the values to a common format.
|Available in the Patterns tab in Column Details Panel|
|By function||You can apply one or more specific functions to cleanse your data of minor errors in formatting or structure.||Edit column with formula in the Transform Builder.|
|Mix-and-match||You can use combinations of the above methods for more complex use cases.|
These standardization techniques assume that your column contains only valid or empty values.
Tip: Standardization may help to cut down the number of invalid values. Before you begin standardizing, however, you should select the red bar in the column histogram to review the values that are invalid for the current type and to fix them via suggestion if possible. For more information, see Find Bad Data.
Using one of the supported matching algorithms, can cluster together similar column values. You can review the clusters of values to determine if they should be mapped to the same value. If so, you can apply the mapping of these values within the application.
For more information, see Overview of Cluster Clean.
For individual columns, can analyze column values for patterns and then provide suggestions for how to normalize the patterned values into a consistent format. For example, the same US phone number can be represented in any of the following methods:
555-1212 415-555-1212 4155551212 (415) 555-1212 +1 (415) 555-1212
Tip: Pattern-based standardization is useful for confirming values in a column to a specific format. This method is applicable to data types like phone numbers, dates, social security numbers, and to a lesser extend email addresses and URLs.
You can apply pattern-based standardization through the Patterns tab. See Column Details Panel.
The following functions can be useful for standardizing values.
All values can be converted to string, so these string functions can be applied to any column if its data type is converted to String data type.
Tip: The clustering algorithms may apply some of these functions to values in your column for purposes of comparison.
|String Conversion||CHAR Function|
|Case Conversion||UPPER Function|
|Cleanse Functions||TRIM Function|
|String Sizing Functions||LEFT Function|
|String Comparison Functions||See Compare Strings.|
supports nesting functions within each other. The following transformation performs some basic cleanup on all columns in your dataset that are of String cleanup.
In the Formula, you see a nested expression. If the value in the column is valid against String data type, then, do the following to the column value:
NOTE: The IFVALID function tests each row value for validation against the specified data type. It does not test the column against the data type. See IFVALID Function.
The net result of this single step applied to all columns is to eliminate whitespace, convert to uppercase, and then truncate the length of each string to only 32 characters.
For more information, see Cleanse Tasks.
You can use the following functions to standardize numeric values.
For the NUMFORMAT function, you can specify the full format to which you want the numeric values in the column to confirm. In the following example, all values that contain a decimal point and match with the Decimal (Float) type are forced to add a value before the decimal. This step converts values like
0.00, which standardizes the format of your numbers.
.). Values that match could possibly be decimals and require further evaluation:
If the value in the column is valid against the Decimal (Float) data type then do the following:
ROUND the value to two decimal points. For more information, see ROUND Function.
Format the value in the following manner:
For more information, see Normalize Numeric Values.
Since dates are structured patterns of string-based data, the best approach is to begin by using the Patterns tab in the Column Details panel. See below.
For more detailed modifications, you can specify formatting strings that are applied as part of the DATEFORMAT function to the dates in your column.
For more information including examples on the DATEFORMAT function, see Format Dates.
You can create custom datatypes to use as a form of standardization. Values in a column that do not conform to the custom type are flagged as invalid and can be triaged accordingly.
NOTE: A custom data type does not inherently provide a means of standardizing the values. The values flagged as invalid must be converted to valid values or removed.
You can upload a dictionary file containing the list of accepted values for the custom type.
NOTE: This method is likely to be superseded by dictionaries that can be applied through the Standardize page.
For more information, see Create Custom Data Types.
A custom data type can be created based on a user-defined regular expression.
NOTE: Regular expressions are powerful tools for creating matching patterns. They are considered developer tools.
For more information, see Create Custom Data Types Using RegEx.