Evaluation functions

Use the evaluation functions to evaluate an expression, based on your events, and return a result.

Quick reference

See the Supported functions and syntax section for a quick reference list of the evaluation functions.

Commands

You can use evaluation functions with the eval, fieldformat, and where commands, and as part of eval expressions with other commands.

Usage

• All functions that accept strings can accept literal strings or any field. 
• All functions that accept numbers can accept literal numbers or any numeric field.

String arguments and fields

For most evaluation functions, when a string argument is expected, you can specify either a literal string or a field name. Literal strings must be enclosed in double quotation marks. In other words, when the function syntax specifies a string you can specify any expression that results in a string. For example, you have a field called name that contains the names of your servers. If you want to append the literal string server at the end of the name, you would use dot notation like this in your search: name."server".​

Nested functions

You can specify a function as an argument to another function.

In the following example, the cidrmatch function is used as the first argument in the if function.

... | eval isLocal=if(cidrmatch("123.132.32.0/25",ip), "local", "not local")

The following example shows how to use the true() function to provide a default to the case function.

... | eval error=case(status == 200, "OK", status == 404, "Not found", true(), "Other")

Supported functions and syntax

There are two ways that you can see information about the supported evaluation functions:

• Function list by category
• Alphabetical list of functions

Function list by category

The following table is a quick reference of the supported evaluation functions, organized by category. This table provides a brief description for each function. Use the links in the table to learn more about each function and to see examples.

Type of function	Supported functions and syntax	Description
Comparison and Conditional functions	case(<condition>,<value>,...)	Accepts alternating conditions and values. Returns the first value for which the condition evaluates to TRUE.
	cidrmatch(<cidr>,<ip>)	Returns TRUE when an IP address, <ip>, belongs to a particular CIDR subnet, <cidr>.
	coalesce(<values>)	Takes one or more values and returns the first value that is not NULL.
	false()	Returns FALSE.
	if(<predicate>,<true_value>,<false_value>)	If the <predicate> expression evaluates to TRUE, returns the <true_value>, otherwise the function returns the <false_value>.
	in(<field>,<list>)	Returns TRUE if one of the values in the list matches a value that you specify.
	like(<str>,<pattern>)	Returns TRUE only if <str> matches <pattern>.
	lookup(<lookup_table>, <json_object>, <json_array>)	Performs a CSV lookup. Returns the output field or fields in the form of a JSON object. The lookup() function is available only to Splunk Enterprise users.
	match(<str>, <regex>)	Returns TRUE if the regular expression <regex> finds a match against any substring of the string value <str>. Otherwise returns FALSE.
	null()	This function takes no arguments and returns NULL.
	nullif(<field1>,<field2>)	Compares the values in two fields and returns NULL if the value in <field1> is equal to the value in <field2>. Otherwise returns the value in <field1>.
	searchmatch(<search_str>)	Returns TRUE if the event matches the search string.
	true()	Returns TRUE.
	validate(<condition>, <value>,...)	Takes a list of conditions and values and returns the value that corresponds to the condition that evaluates to FALSE. This function defaults to NULL if all conditions evaluate to TRUE. This function is the opposite of the case function.
Conversion functions	ipmask(<mask>,<ip>)	Generates a new masked IP address by applying a mask to an IP address using a bitwise AND operation.
	printf(<format>,<arguments>)	Creates a formatted string based on a format description that you provide.
	tonumber(<str>,<base>)	Converts a string to a number.
	tostring(<value>,<format>)	Converts the input, such as a number or a Boolean value, to a string.
Cryptographic functions	md5(<str>)	Computes the md5 hash for the string value.
	sha1(<str>)	Computes the sha1 hash for the string value.
	sha256(<str>)	Computes the sha256 hash for the string value.
	sha512(<str>)	Computes the sha512 hash for the string value.
Date and Time functions	now()	Returns the time that the search was started.
	relative_time(<time>,<specifier>)	Adjusts the time by a relative time specifier.
	strftime(<time>,<format>)	Takes a UNIX time and renders it into a human readable format.
	strptime(<str>,<format>)	Takes a human readable time and renders it into UNIX time.
	time()	The time that eval function was computed. The time will be different for each event, based on when the event was processed.
Informational functions	isbool(<value>)	Returns TRUE if the field value is Boolean.
	isint(<value>)	Returns TRUE if the field value is an integer.
	isnotnull(<value>)	Returns TRUE if the field value is not NULL.
	isnull(<value>)	Returns TRUE if the field value is NULL.
	isnum(<value>)	Returns TRUE if the field value is a number.
	isstr(<value>)	Returns TRUE if the field value is a string.
	typeof(<value>)	Returns a string that indicates the field type, such as Number, String, Boolean, and so forth
JSON functions	json_object(<members>)	Creates a new JSON object from members of key-value pairs.
	json_append(<json>, <path_value_pairs>)	Appends values to the ends of indicated arrays within a JSON document.
	json_array(<values>)	Creates a JSON array using a list of values.
	json_array_to_mv(<json_array>, <boolean>)	Maps the elements of a proper JSON array into a multivalue field.
	json_extend(<json>, <path_value_pairs>)	Flattens arrays into their component values and appends those values to the ends of indicated arrays within a valid JSON document.
	json_extract(<json>, <paths>)	This function returns a value from a piece JSON and zero or more paths. The value is returned in either a JSON array, or a Splunk software native type value.
	json_extract_exact(<json>,<keys>)	Returns Splunk software native type values from a piece of JSON by matching literal strings in the event and extracting them as keys.
	json_keys(<json>)	Returns the keys from the key-value pairs in a JSON object as a JSON array.
	json_set(<json>, <path_value_pairs>)	Inserts or overwrites values for a JSON node with the values provided and returns an updated JSON object.
	json_set_exact(<json>,<key_value_pairs>)	Uses provided key-value pairs to generate or overwrite a JSON object.
	json_valid(<json>)	Evaluates whether piece of JSON uses valid JSON syntax and returns either TRUE or FALSE.
Mathematical functions	abs(<num>)	Returns the absolute value.
	ceiling(<num>)	Rounds the value up to the next highest integer.
	exact(<expression>)	Returns the result of a numeric eval calculation with a larger amount of precision in the formatted output.
	exp(<num>)	Returns the exponential function eN.
	floor(<num>)	Rounds the value down to the next lowest integer.
	ln(<num>)	Returns the natural logarithm.
	log(<num>,<base>)	Returns the logarithm of <num> using <base> as the base. If <base> is omitted, base 10 is used.
	pi()	Returns the constant pi to 11 digits of precision.
	pow(<num>,<exp>)	Returns <num> to the power of <exp>, <num><exp>.
	round(<num>,<precision>)	Returns <num> rounded to the amount of decimal places specified by <precision>. The default is to round to an integer.
	sigfig(<num>)	Rounds <num> to the appropriate number of significant figures.
	sqrt(<num>)	Returns the square root of the value.
	sum(<num>,...)	Returns the sum of numerical values as an integer.
Multivalue eval functions	commands(<value>)	Returns a multivalued field that contains a list of the commands used in <value>.
	mvappend(<values>)	Returns a multivalue result based on all of values specified.
	mvcount(<mv>)	Returns the count of the number of values in the specified field.
	mvdedup(<mv>)	Removes all of the duplicate values from a multivalue field.
	mvfilter(<predicate>)	Filters a multivalue field based on an arbitrary Boolean expression.
	mvfind(<mv>,<regex>)	Finds the index of a value in a multivalue field that matches the regular expression.
	mvindex(<mv>,<start>,<end>)	Returns a subset of the multivalue field using the start and end index values.
	mvjoin(<mv>,<delim>)	Takes all of the values in a multivalue field and appends the values together using a delimiter.
	mvmap(<mv>,<expression>)	This function iterates over the values of a multivalue field, performs an operation using the <expression> on each value, and returns a multivalue field with the list of results.
	mvrange(<start>,<end>,<step>)	Creates a multivalue field based on a range of specified numbers.
	mvsort(<mv>)	Returns the values of a multivalue field sorted lexicographically.
	mvzip(<mv_left>,<mv_right>,<delim>)	Combines the values in two multivalue fields. The delimiter is used to specify a delimiting character to join the two values.
	mv_to_json_array(<field>, <inver_types>)	Maps the elements of a multivalue field to a JSON array.
	split(<str>,<delim>)	Splits the string values on the delimiter and returns the string values as a multivalue field.
Statistical eval functions	avg(<values>)	Returns the average of numerical values as an integer.
	max(<values>)	Returns the maximum of a set of string or numeric values.
	min(<values>)	Returns the minimum of a set of string or numeric values.
	random()	Returns a pseudo-random integer ranging from zero to 231-1.
Text functions	len(<str>)	Returns the count of the number of characters, not bytes, in the string.
	lower(<str>)	Converts the string to lowercase.
	ltrim(<str>,<trim_chars>)	Removes characters from the left side of a string.
	replace(<str>,<regex>,<replacement>)	Substitutes the replacement string for every occurrence of the regular expression in the string.
	rtrim(<str>,<trim_chars>)	Removes the trim characters from the right side of the string.
	spath(<value>,<path>)	Extracts information from the structured data formats XML and JSON.
	substr(<str>,<start>,<length>)	Returns a substring of a string, beginning at the start index. The length of the substring specifies the number of character to return.
	trim(<str>,<trim_chars>)	Trim characters from both sides of a string.
	upper(<str>)	Returns the string in uppercase.
	urldecode(<url>)	Replaces URL escaped characters with the original characters.
Trigonometry and Hyperbolic functions	acos(X)	Computes the arc cosine of X.
	acosh(X)	Computes the arc hyperbolic cosine of X.
	asin(X)	Computes the arc sine of X.
	asinh(X)	Computes the arc hyperbolic sine of X.
	atan(X)	Computes the arc tangent of X.
	atan2(X,Y)	Computes the arc tangent of X,Y.
	atanh(X)	Computes the arc hyperbolic tangent of X.
	cos(X)	Computes the cosine of an angle of X radians.
	cosh(X)	Computes the hyperbolic cosine of X radians.
	hypot(X,Y)	Computes the hypotenuse of a triangle.
	sin(X)	Computes the sine of X.
	sinh(X)	Computes the hyperbolic sine of X.
	tan(X)	Computes the tangent of X.
	tanh(X)	Computes the hyperbolic tangent of X.

Alphabetical list of functions

The following table is a quick reference of the supported evaluation functions, organized alphabetically. This table provides a brief description for each function. Use the links in the table to learn more about each function and to see examples.

Supported functions and syntax	Description	Type of function
abs(<num>)	Returns the absolute value.	Mathematical functions
acos(X)	Computes the arc cosine of X.	Trigonometry and Hyperbolic functions
acosh(X)	Computes the arc hyperbolic cosine of X.	Trigonometry and Hyperbolic functions
asin(X)	Computes the arc sine of X.	Trigonometry and Hyperbolic functions
asinh(X)	Computes the arc hyperbolic sine of X.	Trigonometry and Hyperbolic functions
atan(X)	Computes the arc tangent of X.	Trigonometry and Hyperbolic functions
atan2(X,Y)	Computes the arc tangent of X,Y.	Trigonometry and Hyperbolic functions
atanh(X)	Computes the arc hyperbolic tangent of X.	Trigonometry and Hyperbolic functions
avg(<values>)	Returns the average of numerical values as an integer.	Statistical eval functions
case(<condition>,<value,...)	Accepts alternating conditions and values. Returns the first value for which the condition evaluates to TRUE.	Comparison and Conditional functions
cidrmatch(<cidr>,<ip>)	Returns TRUE when an IP address, <ip>, belongs to a particular CIDR subnet, <cidr>.	Comparison and Conditional functions
ceiling(<num>)	Rounds the value up to the next highest integer.	Mathematical functions
coalesce(<values>)	Takes one or more values and returns the first value that is not NULL.	Comparison and Conditional functions
commands(<value>)	Returns a multivalued field that contains a list of the commands used in <value>.	Multivalue eval functions
cos(X)	Computes the cosine of an angle of X radians.	Trigonometry and Hyperbolic functions
cosh(X)	Computes the hyperbolic cosine of X radians.	Trigonometry and Hyperbolic functions
exact(<expression>)	Returns the result of a numeric eval calculation with a larger amount of precision in the formatted output.	Mathematical functions
exp(<num>)	Returns the exponential function eN.	Mathematical functions
false()	Returns FALSE.	Comparison and Conditional functions
floor(<num>)	Rounds the value down to the next lowest integer.	Mathematical functions
hypot(X,Y)	Computes the hypotenuse of a triangle.	Trigonometry and Hyperbolic functions
if(<predicate>,<true_value>,<false_value>)	If the <predicate> expression evaluates to TRUE, returns the <true_value>, otherwise the function returns the <false_value>.	Comparison and Conditional functions
in(<field>,<list>)	Returns TRUE if one of the values in the list matches a value that you specify.	Comparison and Conditional functions
ipmask(<mask>,<ip>)	The function generates a new masked IP address by applying a mask to an IP address using a bitwise AND operation.	Conversion functions
isbool(<value>)	Returns TRUE if the field value is Boolean.	Informational functions
isint(<value>)	Returns TRUE if the field value is an integer.	Informational functions
isnotnull(<value>)	Returns TRUE if the field value is not NULL.	Informational functions
isnull(<value>)	Returns TRUE if the field value is NULL.	Informational functions
isnum(<value>)	Returns TRUE if the field value is a number.	Informational functions
isstr(<value>)	Returns TRUE if the field value is a string.	Informational functions
json_append(<json>, <path_value_pairs>)	Appends values to the ends of indicated arrays within a JSON document.	JSON functions
json_array(<values>)	Creates a JSON array using a list of values.	JSON functions
json_array_to_mv(<json_array>, <boolean>)	Maps the elements of a proper JSON array into a multivalue field.	JSON functions
json_extend(<json>, <path_value_pairs>)	Flattens arrays into their component values and appends those values to the ends of indicated arrays within a valid JSON document.	JSON functions
json_extract(<json>, <paths>)	Returns a value from a piece JSON and zero or more paths. The value is returned in either a JSON array, or a Splunk software native type value.	JSON functions
json_extract_exact(<json>,<keys>)	Returns Splunk software native type values from a piece of JSON by matching literal strings in the event and extracting them as keys.	JSON functions
json_keys(<json>)	Returns the keys from the key-value pairs in a JSON object. The keys are returned as a JSON array.	JSON functions
json_object(<members>)	Creates a new JSON object from members of key-value pairs.	JSON functions
json_set(<json>, <path_value_pairs>)	Inserts or overwrites values for a JSON node with the values provided and returns an updated JSON object.	JSON functions
json_set_exact(<json>,<key_value_pairs>)	Uses provided key-value pairs to generate or overwrite a JSON object.	JSON functions
json_valid(<json>)	Evaluates whether piece of JSON uses valid JSON syntax and returns either TRUE or FALSE.	JSON functions
len(X)	Returns the count of the number of characters (not bytes) in the string.	Text functions
like(<str>,<pattern>))	Returns TRUE only if <str> matches <pattern>.	Comparison and Conditional functions
ln(<num>)	Returns the natural logarithm.	Mathematical functions
log(<num>,<base>)	Returns the logarithm of <num> using <base> as the base. If <base> is omitted, base 10 is used.	Mathematical functions
lookup(<lookup_table>, <json_object>, <json_array>)	Performs a CSV lookup. Returns the output field or fields in the form of a JSON object. The lookup() function is available only to Splunk Enterprise users.	Comparison and Conditional functions
len(<str>)	Returns the count of the number of characters, not bytes, in the string.	Text functions
lower(<str>)	Converts the string to lowercase.	Text functions
ltrim(<str>,<trim_chars>)	Removes characters from the left side of a string.	Text functions
match(<str>, <regex>)	Returns TRUE if the regular expression <regex> finds a match against any substring of the string value <str>. Otherwise returns FALSE.	Comparison and Conditional functions
max(<values>	Returns the maximum of a set of string or numeric values.	Statistical eval functions
md5(<str>)	Computes the md5 hash for the string value.	Cryptographic functions
min(<values>)	Returns the minimum of a set of string or numeric values.	Statistical eval functions
mvappend(<values)	Returns a multivalue result based on all of values specified.	Multivalue eval functions
mvcount(<mv>)	Returns the count of the number of values in the specified field.	Multivalue eval functions
mvdedup(<mv>)	Removes all of the duplicate values from a multivalue field.	Multivalue eval functions
mvfilter(<predicate>)	Filters a multivalue field based on an arbitrary Boolean expression.	Multivalue eval functions
mvfind(<mv>,<regex>)	Finds the index of a value in a multivalue field that matches the regular expression.	Multivalue eval functions
mvindex(<mv>,<start>,<end>)	Returns a subset of the multivalue field using the start and end index values.	Multivalue eval functions
mvjoin(<mv>,<delim>)	Takes all of the values in a multivalue field and appends the values together using a delimiter.	Multivalue eval functions
mvmap(<mv>,<expression>)	This function iterates over the values of a multivalue field, performs an operation using the <expression> on each value, and returns a multivalue field with the list of results.	Multivalue eval functions
mvrange(<start>,<end>,<step>)	Creates a multivalue field based on a range of specified numbers.	Multivalue eval functions
mvsort(<mv>)	Returns the values of a multivalue field sorted lexicographically.	Multivalue eval functions
mvzip(<mv_left>,<mv_right>,<delim>)	Combines the values in two multivalue fields. The delimiter is used to specify a delimiting character to join the two values.	Multivalue eval functions
mv_to_json_array(<field>, <infer_types>)	Maps the elements of a multivalue field to a JSON array.	JSON functions
now()	Returns the time that the search was started.	Date and Time functions
null()	This function takes no arguments and returns NULL.	Comparison and Conditional functions
nullif(<field1>,<field2>)	Compares the values in two fields and returns NULL if the value in <field1> is equal to the value in <field2>. Otherwise returns the value in <field1>.	Comparison and Conditional functions
pi()	Returns the constant pi to 11 digits of precision.	Mathematical functions
pow(<num>,<exp>)	Returns <num> to the power of <exp>, <num><exp>.	Mathematical functions
printf(<format>,<arguments>)	Creates a formatted string based on a format description that you provide.	Conversion functions
random()	Returns a pseudo-random integer ranging from zero to 231-1.	Statistical eval functions
relative_time(<time>,<specifier>)	Adjusts the time by a relative time specifier.	Date and Time functions
replace(<str>,<regex>,<replacement>)	Substitutes the replacement string for every occurrence of the regular expression in the string.	Text functions
round(<num>,<precision>)	Returns <num> rounded to the amount of decimal places specified by <precision>. The default is to round to an integer.	Mathematical functions
rtrim(<str>,<trim_chars>)	Removes the trim characters from the right side of the string.	Text functions
searchmatch(<search_str>)	Returns TRUE if the event matches the search string.	Comparison and Conditional functions
sha1(<str>)	Computes the sha1 hash for the string value.	Cryptographic functions
sha256(<str>)	Computes the sha256 hash for the string value.	Cryptographic functions
sha512(<stri>)	Computes the sha512 hash for the string value.	Cryptographic functions
sigfig(<num>)	Rounds <num> to the appropriate number of significant figures.	Mathematical functions
sin(X)	Computes the sine of X.	Trigonometry and Hyperbolic functions
sinh(X)	Computes the hyperbolic sine of X.	Trigonometry and Hyperbolic functions
spath(<value>,<path>)	Extracts information from the structured data formats XML and JSON.	Text functions
split(<str>,<delim>)	Splits the string values on the delimiter and returns the string values as a multivalue field.	Multivalue eval functions
sqrt(<num>)	Returns the square root of the value.	Mathematical functions
strftime(<time>,<format>)	Takes a UNIX time and renders it into a human readable format.	Date and Time functions
strptime(<str>,<format>)	Takes a human readable time and renders it into UNIX time.	Date and Time functions
substr(<str>,<start>,<length>)	Returns a substring of a string, beginning at the start index. The length of the substring specifies the number of character to return.	Text functions
sum(<num>,...)	Returns the sum of numerical values as an integer.	Mathematical functions
tan(X)	Computes the tangent of X.	Trigonometry and Hyperbolic functions
tanh(X)	Computes the hyperbolic tangent of X.	Trigonometry and Hyperbolic functions
time()	The time that eval function was computed. The time will be different for each event, based on when the event was processed.	Date and Time functions
tonumber(<str>,<base>)	Converts a string to a number.	Conversion functions
tostring(<value>,<format>)	Converts the input, such as a number or a Boolean value, to a string.	Conversion functions
trim(<str>,<trim_chars>)	Trim characters from both sides of a string.	Text functions
true()	Returns TRUE.	Comparison and Conditional functions
typeof(<value>)	Returns a string that indicates the field type, such as Number, String, Boolean, and so forth.	Informational functions
upper(<str>)	Returns the string in uppercase.	Text functions
urldecode(<url>)	Replaces URL escaped characters with the original characters.	Text functions
validate(<condition>, <value>,...)	Takes a list of conditions and values and returns the value that corresponds to the condition that evaluates to FALSE. This function defaults to NULL if all conditions evaluate to TRUE. This function is the opposite of the case function.	Comparison and Conditional functions

See also

Topics:
Statistical and charting functions

Commands:
eval
fieldformat
where