Help Center/ Log Tank Service/ User Guide/ Log Processing/ DSL Data Processing Syntax (Beta)/ Operator Functions/ String Functions/ Character Set Check

Updated on 2025-09-07 GMT+08:00

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Character Set Check

str_isalnum

Checks whether a string contains only letters and digits.

Format
```
str_isalnum(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "value": "ltsv5"
}
```

Processing rule

e_set("str_isalnum", str_isalnum(v("value")))

Processing result
```
value: ltsv5 
str_isalnum: true
```

str_isalpha

Checks whether a string consists of only letters.

Format
```
str_isalpha(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "value": "ltsv5"
}
```

Processing rule

e_set("str_isalpha", str_isalpha(v("value")))

Processing result
```
value: ltsv5 
str_isalpha: false
```

str_isascii

Checks whether a string is in ASCII.

Format
```
str_isascii(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "value": "{ltsv5}#@"
}
```

Processing rule

e_set("str_isascii", str_isascii(v("value")))

Processing result
```
value: {ltsv5}#@
str_isascii: true
```

str_isdecimal

Checks whether a string consists of only decimal characters.

Format
```
str_isdecimal(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "value": "111"
}
```

Processing rule

e_set("str_isdecimal", str_isdecimal(v("value")))

Processing result
```
value: 111
str_isdecimal: true
```

str_isdigit

Checks whether a string consists of only digits.

Format
```
str_isdigit(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "value": "111"
}
```

Processing rule

e_set("str_isdigit", str_isdigit(v("value")))

Processing result
```
value: 111
str_isdigit: true
```

str_isidentifier

Checks whether a string is a valid Python identifier, or checks whether a variable name is valid.

Format
```
str_isidentifier(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "key": "int"
}
```

Processing rule

e_set("str_isidentifier", str_isidentifier(v("key")))

Processing result
```
key: int
str_isidentifier: true
```

str_islower

Checks whether a string consists of only lowercase letters.

Format
```
str_islower(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "key": "lower"
}
```

Processing rule

e_set("str_islower", str_islower(v("key")))

Processing result
```
key: lower 
str_islower: true
```

str_isnumeric

Checks whether a string consists of only digits.

Format
```
str_isnumeric(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "key": "123W"
}
```

Processing rule

e_set("str_isnumeric", str_isnumeric(v("key")))

Processing result
```
key: 123W 
str_isnumeric: false
```

str_isprintable

Checks whether all characters in a string are printable characters.

Format
```
str_isprintable(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
  "key": "@#11!"
}
```

Processing rule

e_set("str_isprintable",  str_isprintable(v("key")))

Processing result
```
key: @#11!
str_isprintable: true
```

str_isspace

Checks whether a string consists of only space characters.

Format
```
str_isspace(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
  "key": "@#11!"
}
```

Processing rule

e_set("str_isspace",  str_isspace(v("key")))

Processing result
```
key: @#11!
str_isspace: truefalse
```

str_istitle

Checks whether the first letter of each word in a string is uppercase and whether other letters are lowercase.

Format
```
str_istitle(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "key": "Lts Is A Log Service"
}
```

Processing rule

e_set("str_istitle", str_istitle(v("key")))

Processing result

key: Lts Is A Log Service 
str_istitle: true

str_isupper

Checks whether all letters in a string are uppercase.

Format
```
str_isupper(value)
```

Parameter description

Parameter	Type	Mandatory	Description
value	Any (automatically converted to string)	Yes	String to be checked.

Returned result
true/false.

Function example

Test data
```
{
 "key": "LTS"
}
```

Processing rule

e_set("str_isupper", str_istitle(v("key")))

Processing result
```
key: LTS 
str_isupper: true
```

str_uuid

Randomly generates a UUID.

Format
```
str_uuid(lower=true)
```

Parameter description

Parameter	Type	Mandatory	Description
lower	Boolean	No	Whether the letters in the generated UUID are in lowercase. The default value is true, indicating that the letters are in lowercase.

Returned result
true/false.

Function example

Test data: none
Processing rule
```
e_set("UUID", str_uuid())
```

Processing result

UUID: 1acf7e1d-5a6b-4267-b7c1-874c8b70745d

Parent topic: String Functions

Previous topic: Search, Split, and Format

Next topic: Arithmetic Functions

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