Date: Jan 6th 2016
For any one reading this answer, these are the Xpath String functions supported in latest .Net 4.6 framework:
concat: Returns the concatenation of the arguments.
contains: Returns true if the first argument string contains the second argument string; otherwise returns false.
normalize-space: Returns the argument string with the white space stripped.
starts-with: Returns true if the first argument string starts with the second argument string; otherwise returns false.
string: Converts an object to a string.
string-length: Returns the number of characters in the string.
substring: Returns the substring of the first argument starting at the position specified in the second argument and the length specified in the third argument.
substring-after: Returns the substring of the first argument string that follows the first occurrence of the second argument string in the first argument string.
substring-before: Returns the substring of the first argument string that precedes the first occurrence of the second argument string in the first argument string.
translate: Returns the first argument string with occurrences of characters in the second argument string replaced by the character at the corresponding position in the third argument string.
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