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Enso's Expression Syntax

Enso's expression syntax is a simple, yet powerful, way to manipulate data in Enso. It is designed to be familiar to those used to writing SQL formulas or Excel table based functions.

This guide gives and overview of the syntax a summary of the functions currently avaialble.

To enter an expression, choose the <Expression> entry from the dropdown. They can be used in many places where a column is used, such as in a filter or aggregate components.

Currently, it is not possible to use Enso literals inside the expression syntax but this is planned for a later release.

How to use this guide​

In the documentation below, you will see Enso functions with examples. This text plugs into Enso components that accept expressions including the set, filter and aggregate.

An example may show: IF [CATEGORY] = 1 THEN 'Elite' ELSE IF [CATEGORY] = 2 THEN 'Premium' ELSE 'Standard'

Below is how this function would appear in a set component:

If Then Else If

For simple examples below, such as year(2024-07-04) returns 2024, the date shown implies a value from a row in a DATE column.

Below is how this function would appear in a set component:

Year

Functions can also be combined together to create much more complex expressions. For example: if ([Age] > 20) AND ([State] IN ('NY', 'CO', 'CA')) then 'Target Customer' else 'Disqualify'

Below is how this expression would appear in a set component:

Multi-function

Syntax description​

The Expression syntax is similar to that of SQL Server syntax. The key features of the syntax are:

  • Unlike in Enso code, whitespace is ignored.
  • Expressions are case-insenstive for all identifiers, except for column names.
  • Functions are invoked with argument lists in parentheses.
    • The function name is case-insensitive.
    • The first argument of the function is the column to operate on.
  • Some functions allow for a variable number of arguments, for example coalesce and is_in.
  • No support for comments within the expression (at least for version 1).

Literals​

The following literals are supported:

  • Nothing: null or nothing (not case sensitive).
  • Boolean: true, false (not case sensitive).
  • Number: Support for _ separators in numbers. No support for hex, octal or binary literals.
  • Text: Two formats supported:
    • If in double-quotes, then Excel style with only "" as an escape sequence for ". For example: "This is a ""quoted"" string with 'another'.".
    • If in single quotes, then Python style with usual supported escapes. For example: 'This is a "quoted" string with \'another\'.'.
  • Date: Should be written in ISO format, e.g. 2020-01-01 surrounded by # characters. For example, #2020-01-01#.
  • Time: Should be written in ISO format, e.g. 14:00:00 surrounded by # characters. For example, #14:00:00#.
    • Seconds are optional, so #12:00# is also valid.
  • Parts of seconds are optional allowing more precise specification, so #12:00:00.123# is also valid.
  • DateTime: Enso uses ISO format yyyy-mm-dd HH:MM:SS to represent dates and times. To use a date constant in a function, it needs to be specified as an ISO formatted date, surrounded by # characters. For example, 15, April 2020 at 2PM would be represented as #2020-15-04T14:00:00#.
    • As with Time, seconds and part of seconds are optional.
    • Time zone offset is also optional allowing users to specify a shift from UTC.
      Additionally, the name of the TimeZone can be specified in [] brackets either after the offset or on its own.
      If no time zone or offset is passed the local system time zone will be used. Enso uses the ISO format yyyy-mm-dd HH:MM:SS to represent dates and times. If a DateTime value is not in this format, Enso reads it as a char. To convert a column to enable the use of the DateTime functions, use the parse component to do so.

Column Names​

Columns are represented by their name in square brackets, e.g. [First Name]

  • Any closing brackets in the name need to be escaped (by being doubled) if it is part of the column name.
    e.g. [First]] Name] refers to a column named First] Name.
  • Column names will be case-sensitive (unless the backing table allows case-insensitive column names).
  • The column name must be in square brackets.
  • The escaping of ] is based on the Alteryx syntax.

Note: this is different to SQLite, MySQL and Postgres, which use " to identify columns. However, this is consistent with SQL Server, Excel, Tableau and Alteryx syntaxes.

Operators​

The following operators are supported:

  • Arithmetic: +, -, *, /, % (modulo), ^ (power), - (unary minus).
  • Comparison: =, != (and <>), >, >=, <, <=.
    • Note: = and == are equivalent as there is no assignment operation in the expression syntax.
  • Logical: and, or, not (and !).
  • String: + (concatenation).
  • Date: + (addition of period), - (subtraction of period), - (subtraction of another date to a duration).
  • Time: + (addition of a duration), - (subtraction of a duration), - (subtraction of a time).
  • DateTime: + (addition of duration or period), - (subtraction of duration or period), - (subtraction of another date to a duration).

Additional special operators:

  • IS NULL for checking if a value is null.
  • IS EMPTY for checking if a value is null or "".
  • LIKE for comparing against SQL patterns.
  • IN (...) for checking if a value is in a list of values.
  • <input> BETWEEN <lower> AND <upper> for checking if a value is between two values

Precedence​

The following specifies the operator precedence. Operators at the same level have the same precedence and are evaluated left to right.

  • - (unary minus)
  • ^ (power)
  • *, /, %
  • +, -
  • =, != (or <>), >, >=, <, <=
  • IS NULL, IS NOT NULL, IS EMPTY, IS NOT EMPTY, LIKE, NOT LIKE, IN (...), NOT IN (...), BETWEEN <lower> AND <upper>
  • NOT (or !)
  • AND
  • OR

The precedence ensures that expressions are evaluated in the expected order (following the PEDMAS rules). For example, a + b * c would be evaluated as a + (b * c). Please note, that whitespace does not affect the precedence of operators.

Conditional Functions​

A conditional function performs an action or calculation based on a test of data using an IF statement. Use a conditional function to provide a TRUE or FALSE result to highlight or filter out data based on specific criteria. Conditional functions can be used with any data type.

IF condition THEN true ELSE false ENDIF​

  • IF <condition> THEN <true> ELSE <false>. Returns <true> if the <condition> is true, else returns <false>.

  • There must be an ELSE clause, this is not optional.

  • You may optionally include an ENDIF (or END) at the end of the statement.

    Example: IF [CATEGORY] = 1 THEN 'Elite' ELSE 'Standard'

    CATEGORYResult
    2Standard
    1Elite
    1Elite
    3Standard

IF condition1 THEN true1 ELSE IF condition2 THEN true2 ELSE false ENDIF​

IF <condition1> THEN <true1> ELSE IF <condition2> THEN <true2> ELSE <false> ENDIF.: Returns <true1> if the first condition <condition1> is true, else returns <true2> if the second condition <condition2> is true, else returns <false>.

  • Multiple ELSE IF statements can be included.

  • There must be an ELSE clause, this is not optional.

  • You may optionally include an ENDIF (or END) at the end of the statement.

    Example: IF [CATEGORY] = 1 THEN 'Elite' ELSE IF [CATEGORY] = 2 THEN 'Premium' ELSE 'Standard'

    CATEGORYResult
    2Premium
    1Elite
    1Elite
    3Standard

IIF​

IIF (<boolean>,<true>,<false>): Returns <true> if <boolean> is true, else returns <false>.

  • If always evaluates both <true> and <false>, even though it returns only one of them. Because of this, you should watch for undesirable side effects. For example, if evaluating <false> results in a division by zero error, an error occurs even if <boolean> is True.

    Example: IIF ([CATEGORY] = 1,'Elite', 'Standard')

    CATEGORYResult
    2Standard
    1Elite
    1Elite
    3Standard

SWITCH​

There is currenlty no support for SWITCH statements inside the expression syntax.

Functions​

DateTime​

DateTime functions allow you to perform an action or calculation on a date and time value. Use DateTime functions to extract a part of a DateTime value. Enso uses the ISO format yyyy-mm-dd HH:MM:SS to represent dates and times. If a DateTime value is not in this format, Enso reads it as a char. To convert a column to enable the use of the DateTime functions, use the parse component to do so.

  • today() : Returns the current date.

  • now() : Returns the current date and time.

  • time() : Returns the current time.

  • year(<column>) : Returns the numeric value for the year in a date-time value.

    • Example: year(2024-07-04) returns 2024

  • month(<column>) : Returns the numeric month of the year.

    • Example: month(2024-07-04) returns 7

  • day(<column>) : Returns the numeric day of the month.

    • Example: day(2024-07-04) returns 4

  • day_of_week(<column>) : Returns the numeric day of the week (1 Mon - 7 Sun).

    • Example: day_of_week(2024-07-04) returns 4

  • day_of_year(<column>) : Returns the numeric day of the year.

    • Example: day_of_year(2024-07-04) returns 186

  • hour(<column>) : Returns the numeric hour of the day.

    • Example: hour(2024-07-04 12:50.29.25) returns 12

  • minute(<column>) : Returns the numeric minute of the hour.

    • Example: minute(2024-07-04 12:50.29.25) returns 50

  • second(<column>) : Returns the numeric second of the minute.

    • Example: second(2024-07-04 12:50.29.25) returns 29

  • truncate(<column>) : Truncate the decimal part of a number or the time part of a date time.

    • Example: truncate(2024-07-04 12:50.29.25) returns 2024-07-04

Min/Max​

Min/Max functions functions allow you to find the smallest and largest value of a set of values.

  • min(<column1>, <column2>, ...) : Returns the minimum value from set of columns or values.
    • Example: min(5,1,4) returns 1.
  • max(<column1>, <column2>, ...) : Get the minimum value from set of columns or values.
    • Example: max(5,1,4) returns 5.

Text​

Text functions perform operations on text (char) data. Use a text function to cleanse data, convert data to a different format or case, calculate metrics about the data or do other manipulations.

  • format(<column>, <format>) : Format a value using a specific format. The format can be another column.
    • Example: format(1542.0912,'$###0.00') returns $1542.09.
  • text_left(<column>, <length>) : Return the left part of a text, with the character count indicated by <length>. The length can be another column.
    • Example: text_left(United States,4) returns Unit.
  • text_right(<column>, <length>) : Returns the right part of a text, with the character count indicated by <length>. The length can be another column.
    • Example: text_left(United States,4) returns ates.
  • text_length(<column>) : Returns the length of a text column.
    • Example: text_length(United States) returns 13
  • trim(<column>) - Trims whitespace and from both ends.
  • text_replace(<column>, <search>, <replace>) : Replace a part of a text with another text. The search and replace can be another column. No control over case sensitivity.
    • Example: text_replace(United States, States, Kingdom) returns United Kingdom
  • starts_with(<column>, <value>) : Check if a value starts with a specific value. The value can be another column.
    • Example: starts_with(Enso Analytics, En) returns True
  • ends_with(<column>, <value>) : Check if a value ends with a specific value. The value can be another column.
    • Example: ends_with(Enso Analytics, ytics) returns True

Rounding​

  • ceil(<column>) : Round up to the nearest integer.

    • Example: ceil(1.49) returns 2

  • floor(<column>) : Round down to the nearest integer.

    • Example: floor(1.49) returns 1

  • round(<column>, <precision:Integer>, <use_bankers:Boolean>) : Round to a specific precision. use_bankers is often used for rounding currency values, hence 'bankers'. It specifies that ties on rounding are broken by choosing the closest even digit.

    • Example: round([Amount],0,True) would return the following:

    AmountRounded
    2.4992
    2.52
    1.251
    2.513
    3.54

    • Example: round([Amount],0,False) would return the following:

    AmountRounded
    2.4992
    2.53
    1.251
    2.513
    3.54

  • truncate(<column>) : Truncate the decimal part of a number or the time part of a date time.

    • Example: truncate(1.49) returns 1 and truncate(1.98) returns 1.

Selections​

  • at(<column>, <index:Integer>) : Access a value at a specific index.

  • get(<column>, <index:Integer>, <if_out_of_bounds>) : Access a value at a specific index.

  • first(<column>) : Access the first value in that column.

  • last(<column>) : Access the last value.

  • name(<column>) : Access the column name.

  • sort(<column>) : Sort the values in the column. In-Memory only.

    • Example:sort([Amount])

    Input

    TransactionAmount
    12.499
    22.5
    31.25

    Output

    TransactionAmountSorted Amount
    12.4991.25
    22.52.499
    31.252.5
    • Example:sort([Amount], ..Descending)

    Input

    TransactionAmount
    12.499
    22.5
    31.25

    Output

    TransactionAmountSorted Amount
    12.4992.5
    22.52.499
    31.251.25

  • reverse(<column>) : Reverse the order of the values in the column. In-Memory only.

    • Example:reverse([Transaction])

    Input

    TransactionAmount
    12.499
    22.5
    31.25

    Output

    TransactionAmountReversed Transactions
    12.4993
    22.52
    31.251

Logical​

  • coalesce(<column1>, <column2>, ...) : Return the first non-null value
    • Example: coalesce(_Nothing_, Enso) returns Enso
  • like(<column>, <pattern>) : Check if a value matches a SQL pattern. The pattern can be another column.
    • Example: like(Enso Analytics, En%) returns True
  • is_in(<column>, <value1>, <value2>, ...) : Check if a value is in a list of values. All parameters can be columns.
    • Example: is_in(CA, WA, OR, CA) returns True
  • contains(<column>, <value>) : Check if a value is contained. The value can be another column.
    • Example: contains(Enso Analytics, ytics) returns True
  • equals_ignore_case(<column>, <value>) : Check if a value is equal to another value ignoring case. The value can be another column.
    • Example: equals_ignore_case(Enso, ENSO) returns True
  • is_infinite(<column>) : Check if a value is infinite. This condition happens when dividing a non-zero number by zero.
    • Example: is_infinite(101/0) returns True
  • is_nan(<column>) : Check if a value is NaN.
    • Example: is_nan(0/0) returns True
  • is_nothing(<column>) : Check if a value is null.
    • Example: is_nothing(_Nothing_) returns True
  • is_present(<column>) : Check if a value is not null.
    • Example: is_present(any text) returns True

Conversion​

  • auto_cast(<column>) : Auto detect the value type of a column, and casts the value to this data type.

Values​

  • fill_empty(<column>, <value>) : Fill empty values with a specific value (can be another column). Cannot use Previous_Value.
    • Example: fill_empty(_Empty_, N/A) returns N/A
  • fill_nothing(<column>, <value>) : Fill null values with a specific value (can be another column). Cannot use Previous_Value.

    • Example: fill_nothing(_Nothing_, 0) returns 0

Metadata​

  • count(<column>) : Count the number of non-null values.
  • count_nothing(<column>) : Count the number of null values.
  • length(<column>) : Get the length of the column (row count).
  • duplicate_count(<column>) : Count the number of duplicate values previous to the row.

Limited Functionality​

Currently the following functions work but with limited functionality:

  • take(<column>, <count>) - would allow taking a set of values but would probably evaluate badly.
  • drop(<column>, <count>) - would allow dropping a set of values but would probably evaluate badly.
  • parse(<column>) - can only support the auto parsing of a column, no ability to supply type or format.

Examples​

The following show how some simple expressions would be evaluated.

  • [FirstName] + ' ' + [LastName]
    Concatenates the FirstName and LastName columns, putting a space between FirstName and LastName.

  • [FirstName] = 'John'
    Checks if the FirstName column is equal to 'John', creating a True/False column.

  • 123.456
    Creates a constant number column with the value 123.456.

  • ([Age] > 20) AND ([State] IN ('NY', 'CO', 'CA'))
    Creates a column that is true if the Age column is greater than 20 and the State column is in the list NY, CO or CA.

  • if ([Age] > 20) AND ([State] IN ('NY', 'CO', 'CA')) then 'Target Customer' else 'Disqualify'
    Creates a column that contains Target Customer if the Age column is greater than 20 AND the State column is in the list NY, CO or CA. Otherwise it contains Disqualify.