PanoramicData.NCalcExtensions 1.20.16

PanoramicData.NCalcExtensions

Extension functions for NCalc, documentation for which can be found here (source code) and here (good explanation of built-in functions).

Please submit your requests for new functions in the form of pull requests.

To use:

using PanoramicData.NCalcExtensions;

...
var calculation = "lastIndexOf('abcdefg', 'def')";
var nCalcExpression = new Expression(calculation);

// Add the extension functions
nCalcExpression.EvaluateFunction += NCalcExtensions.NCalcExtensions.Extend;

if (nCalcExpression.HasErrors())
{
	throw new FormatException($"Could not evaluate expression: '{calculation}' due to {nCalcExpression.Error}.");
}

return nCalcExpression.Evaluate();

General functions:

• canEvaluate()
• cast()
• concat()
• convert()
• count()
• changeTimeZone()
• dateTime()
• dateTimeAsEpochMs()
• format()
• if()
• in()
• isInfinite()
• isNaN()
• isNull()
• isNullOrEmpty()
• isNullOrWhiteSpace()
• isSet()
• itemAtIndex()
• join()
• jPath()
• length()
• list()
• nullCoalesce()
• regexGroup()
• regexIsMatch()
• retrieve()
• skip()
• store()
• switch()
• take()
• throw()
• timeSpan()
• toDateTime()
• try()
• typeOf()
• where()

String functions:

• capitalize()
• contains()
• endsWith()
• indexOf()
• join()
• lastIndexOf()
• length()
• padLeft()
• parse()
• parseInt() (deprecated - use "parse()" instead)
• replace()
• split()
• startsWith()
• substring()
• toLower()
• toUpper()
• toString()

Supported functions:

---

canEvaluate()

Purpose

Determines whether ALL of the parameters can be evaluated. This can be used, for example, to test whether a parameter is set.

Parameters

• parameter1, parameter2, ...

Examples

• canEvaluate(nonExistent) : false
• canEvaluate(1) : true

---

cast()

Purpose

Cast an object to another (e.g. float to decimal). The method requires that conversion of value to target type be supported.

Parameters

• inputObject
• typeString

Examples

• cast(0.3, 'System.Decimal')

---

changeTimeZone()

Purpose

Change a DateTime's time zone. For a list of supported TimeZone names, see https://docs.microsoft.com/en-us/dotnet/api/system.timezoneinfo.findsystemtimezonebyid?view=netstandard-2.0

Parameters

• source DateTime
• source TimeZone name
• destination TimeZone name

Examples

• changeTimeZone(theDateTime, 'UTC', 'Eastern Standard Time')
• changeTimeZone(theDateTime, 'Eastern Standard Time', 'UTC')

---

concat()

Purpose

Concatenates lists and objects. The examples all result in a List<object?> containing 4 integers: 1, 2, 3 and 4.

Parameters

• the lists or objects to concatenate

Examples

• concat(list(1, 2), list(3, 4))
• concat(list(1, 2, 3, 4))
• concat(1, 2, 3, 4)
• concat(list(1, 2, 3), 4)
• concat(1, list(2, 3, 4))

---

convert()

Purpose

Converts the output of parameter 1 into the result of parameter 2. Can be used to return an empty string instead of the result of parameter 1, which can be useful when the return value is not useful. The result of parameter 1 is available as the variable "value".

Parameters

• the value to calculate
• destination TimeZone name

Examples

• convert(anyFunction(), 'XYZ'): 'XYZ'
• convert(1 + 1, value + 1): 3

---

dateTime()

Purpose

Return the DateTime in the specified format as a string, with an optional offset.

Parameters

• timeZone (only 'UTC' currently supported)
• format
• day offset
• hour offset
• minute offset
• second offset

Examples

• dateTime('UTC', 'yyyy-MM-dd HH:mm:ss', -90, 0, 0, 0) : 90 days ago (e.g. '2019-03-14 05:09')
• dateTime('UTC', 'yyyy-MM-dd HH:mm:ss') : now (e.g. '2019-03-14 05:09')

---

dateTimeAsEpochMs()

Purpose

Parses the input DateTime and outputs as milliseconds since the Epoch (1st Jan 1970).

Parameters

• input date string
• format

Examples

• dateTimeAsEpochMs('20190702T000000', 'yyyyMMddTHHmmssK') : 1562025600000

---

format()

Purpose

Formats strings and numbers as output strings with the specified format

Parameters

• object (number or text)
• format: the format to use

• see C# number and date/time formatting
• weekOfMonth is the numeric week of month as would be shown on a calendar with one row per week with weeks starting on a Sunday
• weekOfMonthText is the same as weekOfMonth, but translated: 1: 'first', 2: 'second', 3: 'third', 4: 'forth', 5: 'last'
• weekDayOfMonth is the number of times this weekday has occurred within the month so far, including this one
• weekDayOfMonthText is the same as weekDayOfMonth, but translated: 1: 'first', 2: 'second', 3: 'third', 4: 'forth', 5: 'last'

• timeZone [optional] - see https://docs.microsoft.com/en-us/dotnet/api/system.timezoneinfo.findsystemtimezonebyid?view=netstandard-2.0

Examples

• format(1, '00') : '01'
• format(1.0, '00') : '01'
• format('2021-11-29', 'dayOfYear') : '333'
• format('2021-11-01', 'weekOfMonth') : 1
• format('2021-11-01', 'weekOfMonthText') : 'first'
• format('2021-11-28', 'weekOfMonth') : 5
• format('2021-11-28', 'weekOfMonthText') : 'last'
• format('2021-11-28', 'weekDayOfMonth') : 4
• format('2021-11-28', 'weekDayOfMonthText') : 'forth'
• format('01/01/2019', 'yyyy-MM-dd') : '2019-01-01'
• format(theDateTime, 'yyyy-MM-dd HH:mm', 'Eastern Standard Time') [where theDateTime is a .NET DateTime, set to DateTime.Parse("2020-03-13 16:00", CultureInfo.InvariantCulture)] : '2020-03-13 12:00'

---

if()

Purpose

Return one of two values, depending on the input function.

Parameters

• condition
• output if true
• output if false

Examples

• if(1 == 1, 'yes', 'no') : 'yes'
• if(1 == 2, 3, 4) : 4

---

in()

Purpose

Determines whether a value is in a set of other values.

Parameters

• list
• item

Examples

• in('needle', 'haystack', 'with', 'a', 'needle', 'in', 'it') : true
• in('needle', 'haystack', 'with', 'only', 'hay') : false

---

indexOf()

Purpose

Determines the first position of a string within another string. Returns -1 if not present.

Parameters

• longString
• shortString

Examples

• indexOf('#abcabc#', 'abc') : 1
• indexOf('#abcabc#', 'abcd') : -1

---

isInfinite()

Purpose

Determines whether a value is infinite

Parameters

• value

Examples

• isInfinite(1/0) : true
• isInfinite(0/1) : false

---

isNaN()

Purpose

Determines whether a value is not a number.

Parameters

• value

Examples

• isNaN(null) : true
• isNaN(1) : false

---

isNull()

Purpose

Determines whether a value is either:

• null; or
• it's a JObject and it's type is JTokenType.Null.

Parameters

• value

Examples

• isNull(1) : false
• isNull('text') : false
• isNull(bob) : true if bob is null
• isNull(null) : true

---

isNullOrEmpty()

Purpose

Determines whether a value is either:

• null; or
• it's a JObject and it's type is JTokenType.Null or;
• it's a string and it's empty.

Parameters

• value

Examples

• isNullOrEmpty(null) : true
• isNullOrEmpty('') : true
• isNullOrEmpty(' ') : false
• isNullOrEmpty(bob) : true if bob is null or whitespace
• isNullOrEmpty(1) : false
• isNullOrEmpty('text') : false

---

isNullOrWhiteSpace()

Purpose

Determines whether a value is either:

• null; or
• it's a JObject and it's type is JTokenType.Null or;
• it's a string and it's empty or only contains whitespace characters (\r, \n, \t, or ' ').

Parameters

• value

Examples

• isNullOrWhiteSpace(null) : true
• isNullOrWhiteSpace('') : true
• isNullOrWhiteSpace(' ') : true
• isNullOrWhiteSpace(bob) : true if bob is null or whitespace
• isNullOrWhiteSpace(1) : false
• isNullOrWhiteSpace('text') : false

---

isSet()

Purpose

Determines whether a parameter is set:

Parameters

• parameter name

Examples

• isSet('a') : true/false depending on whether a is an available variable

---

itemAtIndex()

Purpose

Determines the item at the given index. The first index is 0.

Parameters

• parameter name

Examples

• itemAtIndex(split('a b c', ' '), 1) : 'b'

---

join()

Purpose

Joins a list of strings into a single string.

Parameters

• parameter name

Examples

• join(split('a b c', ' '), ', ') : 'a, b, c'

---

lastIndexOf()

Purpose

Determines the last position of a string within another string. Returns -1 if not present.

Parameters

• longString
• shortString

Examples

• lastIndexOf('#abcabc#', 'abc') : 4
• lastIndexOf('#abcabc#', 'abcd') : -1

---

length()

Purpose

Determines length of a string or IList.

Parameters

• string or IList

Examples

• length('a piece of string') : 17
• length(split('a piece of string', ' ')) : 4

---

nullCoalesce()

Purpose

Returns the first parameter that is not null, otherwise: null.

Parameters

• any number of objects

Examples

• nullCoalesce() : null
• nullCoalesce(1, null) : 1
• nullCoalesce(null, 1, 2, 3) : 1
• nullCoalesce(null, null, null) : null
• nullCoalesce(null, null, 'xxx', 3) : 'xxx'

---

skip()

Purpose

Skips a number of items in a list. If the number of items to skip is greater than the number of items in the list, an empty list is returned.

Parameters

• the list to skip from
• the number of items to skip

Examples

• skip(list(1, 2, 3), 1): list(2, 3)

---

split()

Purpose

Splits a string on a given character into a list of strings.

Parameters

• longString
• character

Examples

• split('a bc d', ' ') : list('a', 'bc', 'd')

---

startsWith()

Purpose

Determines whether a string starts with another string.

Parameters

• longString
• shortString

Examples

• startsWith('abcdefg', 'ab') : true
• startsWith('abcdefg', 'cd') : false

---

endsWith()

Purpose

Determines whether a string ends with another string.

Parameters

• longString
• shortString

Examples

• endsWith('abcdefg', 'fg') : true
• endsWith('abcdefg', 'fgh') : false

---

jPath()

Purpose

Selects a single value from a JObject using a JPath expression

Parameters

• input JObject
• JPath string expression

Examples

sourceJObject JSON:

{
  "name": "bob",
  "numbers": [ 1, 2 ]
  "arrayList": [ 
    { "key": "key1", "value": "value1" },
    { "key": "key2", "value": "value2" } 
  ]
}

• jPath(sourceJObject, 'name') : 'bob'
• jPath(sourceJObject, 'size') : an exception is thrown
• jPath(sourceJObject, 'size', True) : null is returned
• jPath(sourceJObject, 'numbers[0]') : 1
• jPath(sourceJObject, 'arrayList[?(@key==\'key1\')]') : "value1"

---

list()

Purpose

Emits a List<object?> and collapses down lists of lists to a single list.

Parameters

• the parameters

Examples

• list('', 1, '0')
• list(null, 1, '0')
• list(list(null, 1, '0'), 1, '0')

---

padLeft()

Purpose

Pad the left of a string with a character to a desired string length.

Parameters

• stringToPad
• desiredStringLength (must be >=1)
• paddingCharacter

Examples

• padLeft('', 1, '0') : '0'
• padLeft('12', 5, '0') : '00012'
• padLeft('12345', 5, '0') : '12345'
• padLeft('12345', 3, '0') : '12345'

---

parse()

Purpose

Returns the conversion of a string to a numeric type. Supported types are:

• sbyte
• byte
• short
• ushort
• int
• uint
• long
• ulong
• double
• float
• decimal

Parameters

• type (see above)
• text

Examples

• parse('int', '1') : 1

---

parseInt()

Purpose

Returns an integer version of a string.

Parameters

• integerAsString

Examples

• parseInt('1') : 1

---

regexGroup()

Purpose

Selects a regex group capture

Parameters

• input
• regex
• zero-based capture index (default: 0)

Examples

• regexGroup('abcdef', '^ab(.+?)f$') : 'cde'
• regexGroup('abcdef', '^ab(.)+f$') : 'c'
• regexGroup('abcdef', '^ab(.)+f$', 1) : 'd'
• regexGroup('abcdef', '^ab(.)+f$', 2) : 'e'
• regexGroup('abcdef', '^ab(.)+f$', 10) : null

---

regexIsMatch()

Purpose

Determine whether a string matches a regex

Parameters

• input
• regex

Examples

• regexIsMatch('abcdef', '^ab.+') : true
• regexIsMatch('Zbcdef', '^ab.+') : false

---

replace()

Purpose

Replace a string with another string

Parameters

• haystackString
• needleString
• betterNeedleString

Examples

• replace('abcdefg', 'cde', 'CDE') : 'abCDEfg'
• replace('abcdefg', 'cde', '') : 'abfg'

---

retrieve()

Purpose

Retrieves a value from storage

Parameters

• key

Examples

• retrieve('thing')

---

store()

Purpose

Stores a value for use later in the pipeline

Returns

true

Parameters

• key
• value

Examples

• store('thing', 1) : true

---

substring()

Purpose

Retrieves part of a string. If more characters are requested than available at the end of the string, just the available characters are returned.

Parameters

• inputString
• startIndex
• length (optional)

Examples

• substring('haystack', 3) : 'stack'
• substring('haystack', 0, 3) : 'hay'
• substring('haystack', 3, 100) : 'stack'
• substring('haystack', 0, 100) : 'haystack'
• substring('haystack', 0, 0) : ''

---

switch()

Purpose

Return one of a number of values, depending on the input function.

Parameters

• switched value
• a set of pairs: case_n, output_n
• if present, a final value can be used as a default. If the default WOULD have been returned, but no default is present, an exception is thrown.

Examples

• switch('yes', 'yes', 1, 'no', 2) : 1
• switch('blah', 'yes', 1, 'no', 2) : throws exception
• switch('blah', 'yes', 1, 'no', 2, 3) : 3

---

take()

Purpose

Takes a number of items from a list. If a number is provided that is longer than the list, the full list is returned.

Parameters

• the list to take from
• the number of items to take

Examples

• take(list(1, 2, 3), 2): list(1, 2)
• take(list(1, 2, 3), 10): list(1, 2, 3)

---

throw()

Purpose

Throws an NCalcExtensionsException. Useful in an if().

Parameters

• message (optional)

Examples

• throw()
• throw('This is a message')
• if(problem, throw('There is a problem'), 5)

---

timeSpan()

Purpose

Determines the amount of time between two DateTimes. The following units are supported:

• Years
• Weeks
• Days
• Hours
• Minutes
• Seconds
• Milliseconds
• Any other string is handled with TimeSpan.ToString(timeUnit). See https://learn.microsoft.com/en-us/dotnet/standard/base-types/standard-timespan-format-strings

Parameters

• startDateTime
• endDateTime
• timeUnit

Examples

• timeSpan('2019-01-01 00:01:00', '2019-01-01 00:02:00', 'seconds') : 3600

---

toDateTime()

Purpose

Converts a string to a UTC DateTime. May take an optional inputTimeZone.

Note that when using numbers as the first input parameter, provide it as a decimal (see examples, below) to avoid hitting an NCalc bug relating to longs being interpreted as floats.

Parameters

• inputString
• stringFormat
• inputTimeZone (optional) See https://docs.microsoft.com/en-us/dotnet/api/system.timezoneinfo.findsystemtimezonebyid?view=netstandard-2.0

Examples

• toDateTime('2019-01-01', 'yyyy-MM-dd') : A date time representing 2019-01-01
• toDateTime('2020-02-29 12:00', 'yyyy-MM-dd HH:mm', 'Eastern Standard Time') : A date time representing 2020-02-29 17:00:00 UTC
• toDateTime('2020-03-13 12:00', 'yyyy-MM-dd HH:mm', 'Eastern Standard Time') : A date time representing 2020-03-13 16:00:00 UTC
• toDateTime(161827200.0, 's', 'UTC') : A date time representing 1975-02-17 00:00:00 UTC
• toDateTime(156816000000.0, 'ms', 'UTC') : A date time representing 1974-12-21 00:00:00 UTC
• toDateTime(156816000000000.0, 'us', 'UTC') : A date time representing 1974-12-21 00:00:00 UTC

---

toLower()

Purpose

Converts a string to lower case.

Parameters

• string

Examples

• toLower('PaNToMIMe') : 'pantomime'

---

toString()

Purpose

Converts any object to a string

Parameters

• object

Examples

• toString(1) : '1'

---

toUpper()

Purpose

Converts a string to upper case.

Parameters

• string

Examples

• toUpper('PaNToMIMe') : 'PANTOMIME'

---

try()

Purpose

If a function throws an exception, return an alternate value.

Parameters

• function to attempt
• result to return if an exception is thrown (null is returned if this parameter is omitted and an exception is thrown)

Examples

• try(1, 'Failed') : 1
• try(throw('Woo')) : null
• try(throw('Woo'), 'Failed') : 'Failed'
• try(throw('Woo'), exception_message) : 'Woo'
• try(throw('Woo'), exception_type) : typeof(PanoramicData.NCalcExtensions.Exceptions.NCalcExtensionsException)
• try(throw('Woo'), exception_typeFullName) : 'PanoramicData.NCalcExtensions.Exceptions.NCalcExtensionsException'
• try(throw('Woo'), exception_typeName) : 'NCalcExtensionsException'
• try(throw('Woo'), exception) : The Exception object thrown by the throw function.

---

typeOf()

Purpose

Determines the C# type of the object.

Parameters

• parameter

Examples

• typeOf('text') : 'String'
• typeOf(1) : 'Int32'
• typeOf(1.1) : 'Double'
• typeOf(null) : null

---

where()

Purpose

Filters an IEnumerable to bring back only those items that match a condition.

Parameters

• list - the original list
• predicate - a string to represent the value to be evaluated
• nCalcString - the string to evaluate

Examples

• where(list(1, 2, 3, 4, 5), 'n', 'n < 3') : list(1, 2)
• where(list(1, 2, 3, 4, 5), 'n', 'n < 3 || n > 4') : list(1, 2, 5)

---

capitalize()

Purpose

Capitalizes a string.

Parameters

• string

Examples

• capitalize('new year') : 'New Year'

---

contains()

Purpose

Determines whether one string contains another.

Parameters

• string searched-in text
• string searched-for text

Examples

• contains('haystack containing needle', 'needle') : true
• contains('haystack containing only hay', 'needle') : false

---

humanize()

Purpose

Humanizes the value text.

Parameters

• value
• timeUnit

Examples

• humanize(3600, 'seconds') : '1 hour'