Compute Counts

Designer Cloud Powered by Trifacta Enterprise Edition supports computation of counts of rows, columns, and ad-hoc values within your data, so that you can make assessments of the quality, consistency, and statistical validity of your data.

Important Note on Counts

Warning

Any computed counts that you see in the Transformer page are computed from the displayed sample.

These computed counts reflect the entire dataset, only if the data grid is displaying the full dataset:

Figure: Data grid sample is the full dataset.

When the job is executed, however, any computations of counts are applied across the entire dataset.

Visual Profiling

When you run a job, you can enable the profiling of the job results, which renders a visual profile and some statistics on the dataset. This profile is available for review through the application. For more information, see Overview of Visual Profiling.

Row and Column Counts

In the status bar at the bottom of the data grid, you can review the current count of rows and columns in the displayed sample.

Tip

The row and column counts in the status bar may be useful for comparing the changes to these metrics between steps. For example, you can click step 2 in your recipe and then review these metrics. When you click step 3, these metrics may change.

Row counts: Depending on your method of sampling, the row counts may change. For more information, see Overview of Sampling.

Column counts: By default, all columns in the panel are displayed. Column counts should change only if you delete or hide them.

Computed row counts

You can use the following functions to identify and compute the row counts in your dataset.

Function Name	Description
COUNT Function	Generates the count of rows in the dataset. Generated value is of Integer type. Tip Typically, this function is used as part of an aggregation, in which rows are grouped according to shared values in other columns. This function can also be applied without grouping, which is called a flat aggregate. More information on how to apply aggregated counts is below.
ROWNUMBER Function	Generates a new column containing the row number as sorted by the `order` parameter and optionally grouped by the `group` parameter.
SOURCEROWNUMBER Function	Returns the row number of the current row as it appeared in the original source dataset before any steps had been applied. Note This function may fail to return results if the original source row information is not available. For example, if you have performed a join between multiple datasets, the source row number information cannot be computed. Similarly, if you compute this function and then perform a join, the results may not make sense. Tip You can pair this function later with the `MIN` or `MAX` functions to compute the highest and lowest row number information.

Count by Pattern

These transformations allow you to compute counts of literals or patterns in a cell's values. Then, you can perform calculations on this new column of values to compute metrics across the dataset.

Count pattern or text

The following example computes the number of references in the tweet column for My Company:

Transformation Name	`Count matches`
Parameter: Option	Text or pattern
Parameter: Text or pattern to count	'My Company'
Parameter: New column name	tweetCompanyReferences

Suppose, however, that the company has multiple ways in which it is reference. It could be:

My Company
My Co
My Company, Inc.

You can modify the above transformation to use a Wrangle to capture these variations:

Transformation Name	`Count matches`
Parameter: Option	Text or pattern
Parameter: Text or pattern to count	`(My Company\|My Co\|My Company, Inc.)`
Parameter: New column name	tweetCompanyReferences

If needed, you can use the following to add up all of the counts in tweetCompanyReferences to determine the total number.

Note

Keep in mind that this sum reflects only the sum of values in the sample in the data grid. When you run a job containing this calculation, it is applied across all rows in the dataset.

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	SUM(tweetCompanyReferences)
Parameter: New column name	sum_tweetCompanyReferences

Count between patterns

You can also collect counts of values between two patterns within a cell's value. In this manner, you can analyze a more constrained substring of the cell value.

The following transformation calculates the URLs in each row of the msgText column, assuming that the URL begins with http:// or https:// and ends with .com or .net:

Transformation Name	`Count matches`
Parameter: Option	Between two delimiters
Parameter: Starting pattern	`(http\:\/\/\|https\:\/\/)`
Parameter: Include as part of the match	Selected
Parameter: Ending pattern	`(\.com\|\.net)`
Parameter: Includes as part of the match	Selected
Parameter: Ignore case	Selected
Parameter: New column name	countURLs

Count Functions

Aggregated counts

You can perform calculations based on groups that you define as part of the calculation. These groupings, called aggregations, are powerful tools for delivering insightful analysis on your data.

In the following example, several aggregated computations, including the COUNT function are performed on transactional data, which is grouped by region (regionId) and product (prodId):

Transformation Name	`Group by`
Parameter: Group by 1	regionId
Parameter: Group by 2	prodId
Parameter: Values 1	SUM(sales)
Parameter: Values 2	COUNT()
Parameter: Type	Group by as new column(s)