CSV: Apply formulas to columns
Use this action to apply a formula to one or more columns for each row in a CSV file, and save the results to a new CSV file. Formulas are written in Javascript.
To apply formulas to a data table the same way, use the Tables: Apply formulas to columns action. CSVs process faster and support higher row limits.
This is an advanced action that requires Javascript. This article provides an overview of the Javascript in the row formula function, but doesn’t cover Javascript extensively.
How to configure this action
This action takes a Javascript formula from the row formula field and executes it for every row. For example, the table below has a Price
and Quantity
column, and two empty columns, Total
and Formatted Total
.
Fruit  Price  Quantity  Total  Formatted Total 

Apple  10  5  
Banana  40  8  
Pears, Bananas  20  2 
Row formulas use basic Javascript notation to calculate new values based on rows and columns, like adding two values together, then saving the result to a column.
A simplified example of the formula notation is Destination column = Column A + Column B
, like Total Column = Price + Quantity
. All columns used in the formula must exist in the table; new columns can’t be added with this action. Here are some example row formulas:
Example row formula  Row formula effect  Result 

columns['total'] = columns[2] * columns[3] 
Set the Total column to Price (col2) * Quantity (col3) 
50 
columns['Formatted Total'] = '$' + columns[2] * columns[3] + '.00' 
Set the Formatted Total column to Price (col2) * Quantity (col3) and prepend $ and append .00 
$50.00 
columns['total'] = columns['total'].replace(/,/ig, "") 
Remove all commas from the Total column. 
Pears Bananas 
columns['total'] = columns[2] * columns[3];columns['Formatted Total'] = '$' + columns[2] * columns[3] + '.00 
Update the Total and Formatted Total columns in one row formula 
50 , $50.00 
Using the last example,
columns['total'] = columns[2] * columns[3];
columns['Formatted Total'] = '$' + columns[2] * columns[3] + '.00'
The entire Total
and Formatted Total
columns are set in one row formula, with the result of:
Fruit  Price  Quantity  Total  Formatted Total 

Apple  10  5  50  $50.00 
Banana  40  8  320  $320.00 
Pears, Bananas  20  2  40  $40.00 
Apply formulas to all columns
Be default, this action applies a formula to every row in a column. It’s possible to also apply a formula to every row in a column, for every column. This will effectively apply a formula to all data in the table.
To do so, start with the following formula template:
var i = 1
while (i < 100) {
columns[i] = "X";
i++;
}
Then, change "X"
to adjust what happens to each column. For example, to replace all quotation marks in all columns, you could use this formula:
var i = 1
while (i < 100) {
columns[i] = columns[i].replace(/“/g, ’’);
i++;
}
Fields for this action

CSV file
 Choose a CSV file you want to apply formulas to. Use a field reference to a file uploaded in a prior task or instance.

Header row
 Select
True
orFalse
from the drop down. Select
True
if the file includes column header on the first row.  Select
False
to include the first row in the formula if the file does not have a header row.
 Select
 Select

Row formula
 Enter the row formula to apply to the CSV column. Use a combination of columns, text, and fields.
 Reference columns in a formula by their name
columns['Column Name']
or ordercolumns[1]
, with 1 being the first column. 
To quickly add row numbers to every row in a CSV, see the Add row numbers to make joining tables easier below.
💡 Tip: Use a JavaScript editor like https://repl.it/languages/javascript to write up the formula, then copy and paste the code over.

Output field name
 Enter the name of the field in which the new CSV should be saved.
Add row numbers to make joining CSVs easier
Use the formula notation: Destination column = rowIndex
to quickly assign row numbers to every row. Then, easily join CSVs by using a related column between them with the CSV: Update file with another file.
Using the syntax above, we add a row number to the column Row Number
with the following formula:
columns['Row Number'] = rowIndex
Row Number  Fruit  Price 

1  Apple  10 
2  Banana  40 
3  Pear  20 
What will this output?
The expected output for this action is a new CSV file with any row formulas applied. The name of the output field will be the Output field name defined during configuration.
Since row formulas may automatically replace data, a new CSV is always created. This action will never edit the source CSV.
Output fields for this action
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