Freemarker operation string

1. substring (START, end) truncates a substring from a string.
Start: The index starting from the substring. Start must be greater than or equal to 0 and less than or equal to end.
End: Specifies the length of a substring. The end value must be greater than or equal to 0 and smaller than or equal to the string length. If this parameter is omitted, the default value is the string length.
Example:
$ {'Str '? Substring (0)} à result: Str
$ {'Str '? Substring (1)} à returns tr
$ {'Str '? Substring (2)} à result: R
$ {'Str '? Substring (3)}. The result is
$ {'Str '? Substring ()}. The result is
$ {'Str '? Substring (0, 1)} à result: S
$ {'Str '? Substring ()} à result is St
$ {'Str '? Substring ()} à returns Str

2. cap_first converts the first letter of the word in the string to uppercase.
$ {'Str '? Cap_first} à returns Str
3. uncap_first converts the initial character of the first word in the string to lowercase.
$ {'Str '? Cap_first} à returns Str
4. capitalize converts the first letter of all words in the string to uppercase.
$ {'Str '? Capitalize} à result: Str

5. convert a string to a date by date, time, and datetime.
For example:
<# Assign date1 = "2009-10-12 "? Date ("yyyy-mm-dd")>
<# Assign date2 = "9:28:20 "? Time ("HH: mm: SS")>
<# Assign date3 = "9:28:20 "? Time ("HH: mm: SS")>
$ {Date1} à result:
The result of $ {date2} à is 9:28:20.
$ {Date3} à result: 9:28:20
Note: If the specified string format is incorrect, an error is thrown.

6. ends_with: determines whether a string ends with a substring and returns a Boolean value.
$ {"String "? Ends_with ("ing ")? String} returns true.
Note: boolean values must be converted to strings before output.

7. html is used to replace <,>, &, and "with the corresponding & lt; & gt; & quot: & amp

8. index_of (substring, start) searches for a substring in the string and returns the index of the first character of the substring. If no substring is found,-1 is returned.
The start parameter is used to specify the index where the string is searched. The start parameter is a numerical value.
If start is greater than the string length, the start value is equal to the string length. If start is less than 0, the start value is 0.
$ {"String "? Index_of ("in") à result is 3
$ {"String "? Index_of ("AB") à result is-1

9. Length returns the string length $ {"string "? Length}. The result is 6.

10. Use lower_case to convert the string to lowercase.
$ {"String "? Lower_case} à result: String

11. upper_case converts strings into uppercase letters.
$ {"String "? Upper_case} à result: String

12. Contains determines whether a character contains a substring. Returns a Boolean value.
$ {"String "? Contains ("ing ")? String}. The result is true.
Note: boolean values must be converted to strings before output.

13. number converts a string to a number.
${111.11 "? Number}. The result is 111.11.

14. Replace replaces a portion of the string with another string from left to right.
$ {"Strabg "? Replace ("AB", "in")}. The result is string.

15. Split Splits a string into a group of strings using the specified delimiter.

<# List "This | is | split "? Split ("|") as S>
$ {S}
</# List>
Result:
This
Is
Split

16. Trim deletes the leading and trailing spaces of a string $ {"string "? Trim} à result is string