4.3.2.3. String functions
The following functions support string operations.
In FEEL, Unicode characters are counted based on their code points.
- substring( string, start position, length? )
Returns the substring from the start position for the specified length. The first character is at position value
1
.表4.16 Parameters
Parameter Type string
string
start position
number
length
(Optional)number
Examples
substring( "testing",3 ) = "sting" substring( "testing",3,3 ) = "sti" substring( "testing", -2, 1 ) = "n" substring( "\U01F40Eab", 2 ) = "ab"
注記In FEEL, the string literal
"\U01F40Eab"
is the🐎ab
string (horse symbol followed bya
andb
).
- string length( string )
Calculates the length of the specified string.
表4.17 Parameters
Parameter Type string
string
Examples
string length( "tes" ) = 3 string length( "\U01F40Eab" ) = 3
- upper case( string )
Produces an uppercase version of the specified string.
表4.18 Parameters
Parameter Type string
string
Example
upper case( "aBc4" ) = "ABC4"
- lower case( string )
Produces a lowercase version of the specified string.
表4.19 Parameters
Parameter Type string
string
Example
lower case( "aBc4" ) = "abc4"
- substring before( string, match )
Calculates the substring before the match.
表4.20 Parameters
Parameter Type string
string
match
string
Examples
substring before( "testing", "ing" ) = "test" substring before( "testing", "xyz" ) = ""
- substring after( string, match )
Calculates the substring after the match.
表4.21 Parameters
Parameter Type string
string
match
string
Examples
substring after( "testing", "test" ) = "ing" substring after( "", "a" ) = ""
- replace( input, pattern, replacement, flags? )
Calculates the regular expression replacement.
表4.22 Parameters
Parameter Type input
string
pattern
string
replacement
string
flags
(Optional)string
注記This function uses regular expression parameters as defined in XQuery 1.0 and XPath 2.0 Functions and Operators.
Example
replace( "abcd", "(ab)|(a)", "[1=$1][2=$2]" ) = "[1=ab][2=]cd"
- contains( string, match )
Returns
true
if the string contains the match.表4.23 Parameters
Parameter Type string
string
match
string
Example
contains( "testing", "to" ) = false
- starts with( string, match )
Returns
true
if the string starts with the match表4.24 Parameters
Parameter Type string
string
match
string
Example
starts with( "testing", "te" ) = true
- ends with( string, match )
Returns
true
if the string ends with the match.表4.25 Parameters
Parameter Type string
string
match
string
Example
ends with( "testing", "g" ) = true
- matches( input, pattern, flags? )
Returns
true
if the input matches the regular expression.表4.26 Parameters
Parameter Type input
string
pattern
string
flags
(Optional)string
注記This function uses regular expression parameters as defined in XQuery 1.0 and XPath 2.0 Functions and Operators.
Example
matches( "teeesting", "^te*sting" ) = true
- split( string, delimiter )
Returns a list of the original string and splits it at the delimiter regular expression pattern.
表4.27 Parameters
Parameter Type string
string
delimiter
string
for a regular expression pattern注記This function uses regular expression parameters as defined in XQuery 1.0 and XPath 2.0 Functions and Operators.
Examples
split( "John Doe", "\\s" ) = ["John", "Doe"] split( "a;b;c;;", ";" ) = ["a","b","c","",""]