String Operators
String operators provide functionality for string manipulation and comparison in DataLogic-rs rules.
cat
The cat operator concatenates multiple strings together.
Syntax
{ "cat": [string1, string2, ...] }Parameters
| Parameter | Description |
|---|---|
| strings | An array of strings or expressions that evaluate to strings |
Example: Simple String Concatenation
Rule:
xxxxxxxxxx{"cat": ["Hello, ", "world!"]}Data:
xxxxxxxxxx{}Result:
xxxxxxxxxx"Hello, world!"Example: Concatenation with Variables
Rule:
xxxxxxxxxx{"cat": [ "Hello, ", {"val": "name"}, "! You are ", {"val": "age"}, " years old."]}Data:
xxxxxxxxxx{"name": "Alice", "age": 30}Result:
xxxxxxxxxx"Hello, Alice! You are 30 years old."substr
The substr operator extracts a substring from a string, starting at a specified position
and optionally extracting a specified number of characters.
Syntax
{ "substr": [string, start_index, length] }Parameters
| Parameter | Description |
|---|---|
| string | The input string to extract from |
| start_index | The start position (0-indexed) |
| length (optional) | The number of characters to extract (if omitted, extracts until end of string) |
Example: Extract Substring
Rule:
xxxxxxxxxx{"substr": ["DataLogic-rs", 4, 5]}Data:
xxxxxxxxxx{}Result:
xxxxxxxxxx"Logic"Example: Extract to End of String
Rule:
xxxxxxxxxx{"substr": [ {"val": "email"}, 5]}Data:
xxxxxxxxxx{"email": "user@example.com"}Result:
xxxxxxxxxx"@example.com"starts_with
The starts_with operator checks if a string starts with a specified prefix.
Syntax
{ "starts_with": [string, prefix] }Parameters
| Parameter | Description |
|---|---|
| string | The string to check |
| prefix | The prefix to look for at the start of the string |
Example: Check if string starts with prefix
Rule:
xxxxxxxxxx{"starts_with": [{"var": "text"}, "Hello"]}Data:
xxxxxxxxxx{"text": "Hello World"}Result:
xxxxxxxxxxtrueExample: Case sensitivity
Rule:
xxxxxxxxxx{"starts_with": [{"var": "text"}, "hello"]}Data:
xxxxxxxxxx{"text": "Hello World"}Result:
xxxxxxxxxxfalseends_with
The ends_with operator checks if a string ends with a specified suffix.
Syntax
{ "ends_with": [string, suffix] }Parameters
| Parameter | Description |
|---|---|
| string | The string to check |
| suffix | The suffix to look for at the end of the string |
Example: Check if string ends with suffix
Rule:
xxxxxxxxxx{"ends_with": [{"var": "text"}, "World"]}Data:
xxxxxxxxxx{"text": "Hello World"}Result:
xxxxxxxxxxtrueExample: Using with conditional
Rule:
xxxxxxxxxx{"if": [ {"ends_with": [{"var": "filename"}, ".txt"]}, "Text file", "Other file"]}Data:
xxxxxxxxxx{"filename": "document.txt"}Result:
xxxxxxxxxx"Text file"upper
The upper operator converts a string to uppercase.
Syntax
{ "upper": string }Parameters
| Parameter | Description |
|---|---|
| string | The string to convert to uppercase |
Example: Convert string to uppercase
Rule:
xxxxxxxxxx{"upper": {"var": "text"}}Data:
xxxxxxxxxx{"text": "Hello World"}Result:
xxxxxxxxxx"HELLO WORLD"Example: Combining with other operators
Rule:
xxxxxxxxxx{"upper": {"substr": [{"var": "text"}, 0, 5]}}Data:
xxxxxxxxxx{"text": "hello world"}Result:
xxxxxxxxxx"HELLO"lower
The lower operator converts a string to lowercase.
Syntax
{ "lower": string }Parameters
| Parameter | Description |
|---|---|
| string | The string to convert to lowercase |
Example: Convert string to lowercase
Rule:
xxxxxxxxxx{"lower": {"var": "text"}}Data:
xxxxxxxxxx{"text": "Hello World"}Result:
xxxxxxxxxx"hello world"Example: Case-insensitive comparison
Rule:
xxxxxxxxxx{"==": [ {"lower": {"var": "userInput"}}, "hello world"]}Data:
xxxxxxxxxx{"userInput": "HELLO WORLD"}Result:
xxxxxxxxxxtruetrim
The trim operator removes whitespace characters from the beginning and end of a string.
Syntax
{ "trim": string }Parameters
| Parameter | Description |
|---|---|
| string | The string to trim |
Example: Remove leading and trailing whitespace
Rule:
xxxxxxxxxx{"trim": {"var": "text"}}Data:
xxxxxxxxxx{"text": " Hello World "}Result:
xxxxxxxxxx"Hello World"Example: Combine with other operators
Rule:
xxxxxxxxxx{"starts_with": [ {"trim": {"var": "text"}}, "Hello"]}Data:
xxxxxxxxxx{"text": " Hello World "}Result:
xxxxxxxxxxtrue