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
which contains the names of your servers. You want to append the literal string server
at the end of the name. You would specify this: 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. This table lists the syntax and provides a brief description for each of the functions. Use the links in the Type of function column for more details and examples.
Type of function  Supported functions and syntax  Description 

Comparison and Conditional functions  case(X,"Y",...)

Accepts alternating conditions and values. Returns the first value for which the condition evaluates to TRUE. 
cidrmatch("X",Y)

Returns TRUE or FALSE based on whether an IP address matches a CIDR notation.  
coalesce(X,...)

This function takes an arbitrary number of arguments and returns the first value that is not NULL.  
false()

Returns FALSE.  
if(X,Y,Z)

If the condition X evaluates to TRUE, returns Y, otherwise returns Z.  
in(FIELD, VALUELIST)

The function returns TRUE if one of the values in the list matches a value in the field you specify.  
like(TEXT, PATTERN)

Returns TRUE if TEXT matches PATTERN.  
match(SUBJECT, "REGEX")

Returns TRUE or FALSE based on whether REGEX matches SUBJECT  
null()

This function takes no arguments and returns NULL.  
nullif(X,Y)

This function is used to compare fields. The function takes two arguments, X and Y, and returns NULL if X = Y. Otherwise it returns X.  
searchmatch(X)

Use this function to return TRUE if the search string (X) matches the event.  
true()

Returns TRUE.  
validate(X,Y,...)

Use this function to return the string Y corresponding to the first expression X that evaluates to FALSE. This function is the opposite of the case function.
 
Conversion functions  printf("format",arguments)

Creates a formatted string based on a format description that you provide. 
tonumber(NUMSTR,BASE)

Converts a string to a number.  
tostring(X,Y)

Converts the input, such as a number or a Boolean value, to a string.  
Cryptographic functions  md5(X)

Computes the md5 hash for the value X. 
sha1(X)

Computes the sha1 hash for the value X.  
sha256(X)

Computes the sha256 hash for the value X.  
sha512(X)

Computes the sha512 hash for the value X.  
Date and Time functions  now()

Returns the time that the search was started. 
relative_time(X,Y)

Adjusts the time by a relative time specifier.  
strftime(X,Y)

Takes a UNIX time and renders it into a human readable format.  
strptime(X,Y)

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(X)

Returns TRUE if the field value is Boolean. 
isint(X)

Returns TRUE if the field value is an integer.  
isnotnull(X)

Returns TRUE if the field value is not NULL.  
isnull(X)

Returns TRUE if the field value is NULL.  
isnum(X)

Returns TRUE if the field value is a number.  
isstr(X)

Returns TRUE if the field value is a string.  
typeof(X)

Returns a string that indicates the field type, such as Number, String, Boolean, and so forth  
Mathematical functions  abs(X)

Returns the absolute value. 
ceiling(X) or ceil(X)

Rounds the value up to the next highest integer.  
exact(X)

Returns the result of a numeric eval calculation with a larger amount of precision in the formatted output.  
exp(X)

Returns the exponential function e^{X} .
 
floor(X)

Rounds the value down to the next lowest integer.  
ln(X)

Returns the natural logarithm.  
log(X,Y)

Returns the logarithm of X using Y as the base. If Y is omitted, base 10 is used.  
pi()

Returns the constant pi to 11 digits of precision.  
pow(X,Y)

Returns X to the power of Y, X^{Y} .
 
round(X,Y)

Returns X rounded to the amount of decimal places specified by Y. The default is to round to an integer.  
sigfig(X)

Rounds X to the appropriate number of significant figures.  
sqrt(X)

Returns the square root of the value.  
Multivalue eval functions  commands(X)

Returns a multivalued field that contains a list of the commands used in X. 
mvappend(X,...)

Returns a multivalue result based on all of values specified.  
mvcount(MVFIELD)

Returns the count of the number of values in the specified field.  
mvdedup(X)

Removes all of the duplicate values from a multivalue field.  
mvfilter(X)

Filters a multivalue field based on an arbitrary Boolean expression X.  
mvfind(MVFIELD,"REGEX")

Finds the index of a value in a multivalue field that matches the REGEX.  
mvindex(MVFIELD,STARTINDEX,ENDINDEX)

Returns a set of values from a multivalue field described by STARTINDEX and ENDINDEX.  
mvjoin(MVFIELD,STR)

Takes all of the values in a multivalue field and appends them together delimited by STR.  
mvrange(X,Y,Z)

Creates a multivalue field with a range of numbers between X and Y, incrementing by Z.  
mvsort(X)

Returns the values of a multivalue field sorted lexicographically.  
mvzip(X,Y,"Z")

Takes two multivalue fields, X and Y, and combines them by stitching together the first value of X with the first value of field Y, then the second with the second, and so on.  
split(X,"Y")

Returns a mv field splitting X by the delimited character Y.  
Statistical eval functions  max(X,...)

Returns the maximum of the string or numeric values. 
min(X,...)

Returns the minimum of the string or numeric values.  
random()

Returns a pseudorandom integer ranging from zero to 2^{31}1.  
Text functions  len(X)

Returns the count of the number of characters (not bytes) in the string. 
lower(X)

Converts the string to lowercase.  
ltrim(X,Y)

Trims the characters represented in Y from the left side of the string.  
replace(X,Y,Z)

Returns a string formed by substituting string Z for every occurrence of regex string Y in string X.  
rtrim(X,Y)

Returns X with the characters in Y trimmed from the right side.  
spath(X,Y)

Extracts a value from a structured data type (XML or JSON) in X based on a location path in Y.  
substr(X,Y,Z)

Returns a substring from X based on the starting position Y and the length Z.  
trim(X,Y)

Trims the characters represented in Y from both sides of the string X.  
upper(X)

Returns the string in uppercase.  
urldecode(X)

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
Supported functions and syntax  Description  Type of function 

abs(X)

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 
case(X,"Y",...)

Accepts alternating conditions and values. Returns the first value for which the condition evaluates to TRUE.  Comparison and Conditional functions 
cidrmatch("X",Y)

Returns TRUE or FALSE based on whether an IP address matches a CIDR notation.  Comparison and Conditional functions 
ceiling(X)

Rounds the value up to the next highest integer.  Mathematical functions 
coalesce(X,...)

This function takes an arbitrary number of arguments and returns the first value that is not NULL.  Comparison and Conditional functions 
commands(X)

Returns a multivalued field that contains a list of the commands used in X.  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(X)

Returns the result of a numeric eval calculation with a larger amount of precision in the formatted output.  Mathematical functions 
exp(X)

Returns the exponential function e^{X} .

Mathematical functions 
false()

Returns FALSE.  Comparison and Conditional functions 
floor(X)

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(X,Y,Z)

If the condition X evaluates to TRUE, returns Y, otherwise returns Z.  Comparison and Conditional functions 
in(VALUELIST)

The function returns TRUE if one of the values in the list matches a value in the field you specify.  Comparison and Conditional functions 
isbool(X)

Returns TRUE if the field value is Boolean.  Informational functions 
isint(X)

Returns TRUE if the field value is an integer.  Informational functions 
isnotnull(X)

Returns TRUE if the field value is not NULL.  Informational functions 
isnull(X)

Returns TRUE if the field value is NULL.  Informational functions 
isnum(X)

Returns TRUE if the field value is a number.  Informational functions 
isstr(X)

Returns TRUE if the field value is a string.  Informational functions 
len(X)

Returns the count of the number of characters (not bytes) in the string.  Text functions 
like(TEXT, PATTERN)

Returns TRUE if TEXT matches PATTERN.  Comparison and Conditional functions 
ln(X)

Returns the natural logarithm.  Mathematical functions 
log(X,Y)

Returns the logarithm of X using Y as the base. If Y is omitted, base 10 is used.  Mathematical functions 
lower(X)

Converts the string to lowercase.  Text functions 
ltrim(X,Y)

Trims the characters represented in Y from the left side of the string.  Text functions 
match(SUBJECT, "REGEX")

Returns TRUE or FALSE based on whether REGEX matches SUBJECT.  Comparison and Conditional functions 
max(X,...)

Returns the maximum of the string or numeric values.  Statistical eval functions 
md5(X)

Computes the md5 hash for the value X.  Cryptographic functions 
min(X,...)

Returns the minimum of the string or numeric values.  Statistical eval functions 
mvappend(X,...)

Returns a multivalue result based on all of values specified.  Multivalue eval functions 
mvcount(MVFIELD)

Returns the count of the number of values in the specified field.  Multivalue eval functions 
mvdedup(X)

Removes all of the duplicate values from a multivalue field.  Multivalue eval functions 
mvfilter(X)

Filters a multivalue field based on an arbitrary Boolean expression X.  Multivalue eval functions 
mvfind(MVFIELD,"REGEX")

Finds the index of a value in a multivalue field that matches the REGEX.  Multivalue eval functions 
mvindex(MVFIELD,STARTINDEX,ENDINDEX)

Returns a set of values from a multivalue field described by STARTINDEX and ENDINDEX.  Multivalue eval functions 
mvjoin(MVFIELD,STR)

Takes all of the values in a multivalue field and appends them together delimited by STR.  Multivalue eval functions 
mvrange(X,Y,Z)

Creates a multivalue field with a range of numbers between X and Y, incrementing by Z.  Multivalue eval functions 
mvsort(X)

Returns the values of a multivalue field sorted lexicographically.  Multivalue eval functions 
mvzip(X,Y,"Z")

Takes two multivalue fields, X and Y, and combines them by stitching together the first value of X with the first value of field Y, then the second with the second, and so on.  Multivalue eval 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(X,Y)

This function is used to compare fields. The function takes two arguments, X and Y, and returns NULL if X = Y. Otherwise it returns X.  Comparison and Conditional functions 
pi()

Returns the constant pi to 11 digits of precision.  Mathematical functions 
pow(X,Y)

Returns X to the power of Y, X^{Y} .

Mathematical functions 
printf("format",arguments)

Creates a formatted string based on a format description that you provide.  Conversion functions 
random()

Returns a pseudorandom integer ranging from zero to 2^{31}1.  Statistical eval functions 
relative_time(X,Y)

Adjusts the time by a relative time specifier.  Date and Time functions 
replace(X,Y,Z)

Returns a string formed by substituting string Z for every occurrence of regex string Y in string X.  Text functions 
round(X,Y)

Returns X rounded to the amount of decimal places specified by Y. The default is to round to an integer.  Mathematical functions 
rtrim(X,Y)

Returns X with the characters in Y trimmed from the right side.  Text functions 
searchmatch(X)

Use this function to return TRUE if the search string (X) matches the event.  Comparison and Conditional functions 
sha1(X)

Computes the md5 hash for the value X.  Cryptographic functions 
sha256(X)

Computes the md5 hash for the value X.  Cryptographic functions 
sha512(X)

Computes the sha512 hash for the value X.  Cryptographic functions 
sigfig(X)

Rounds X 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(X,Y)

Extracts a value from a structured data type (XML or JSON) in X based on a location path in Y.  Text functions 
split(X,"Y")

Returns a mv field splitting X by the delimited character Y.  Multivalue eval functions 
sqrt(X)

Returns the square root of the value.  Mathematical functions 
strftime(X,Y)

Takes a UNIX time and renders it into a human readable format.  Date and Time functions 
strptime(X,Y)

Takes a human readable time and renders it into UNIX time.  Date and Time functions 
substr(X,Y,Z)

Returns a substring from X based on the starting position Y and the length Z.  Text 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(NUMSTR,BASE)

Converts a string to a number.  Conversion functions 
tostring(X,Y)

Converts the input, such as a number or a Boolean value, to a string.  Conversion functions 
trim(X,Y)

Trims the characters represented in Y from both sides of the string X.  Text functions 
true()

Returns TRUE.  
typeof(X)

Returns a string that indicates the field type, such as Number, String, Boolean, and so forth.  Informational functions 
upper(X)

Returns the string in uppercase.  Text functions 
urldecode(X)

Replaces URL escaped characters with the original characters.  Text functions 
validate(X,Y,...)

Use this function to return the string Y corresponding to the first expression X that evaluates to FALSE. This function is the opposite of the case function.

Comparison and Conditional functions 
See also
Topics:
Statistical and charting functions
Commands:
eval
fieldformat
where
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Comments
"You can use evaluation functions with the eval, fieldformat, and where commands, and as part of evaluation expressions." should be "You can use evaluation functions with the eval, fieldformat, and where commands, and as part of eval expressions." to match what is repeatedly stated in the individual function documentation. This said, I fail to see the difference between using "evaluation functions with the eval" command and using "evaluation functions [...] as part of eval expressions." Please enlighten me.
DUThibault
The eval functions are not the same as eval expressions.
* Eval functions are supported with a specific set of commands: eval, fieldformat, and where.
* However, you can use eval expressions with other commands such as chart and timechart.
I will try to clarify that in the section that you reference.