compareVersion
Compare Two Package Version Numbers
Description
Compares two package version numbers to see which one is more recent.
Usage
compareVersion(a, b)
Arguments
  
| a | a character string containing the first version 
number to compare. | 
  | b | a character string containing the second version 
number to compare. | 
 
Details
A version number string contains a sequence of non-negative
integers separated by periods or hyphens, such as 1.2
or 1.2-17.
compareVersion(a,b) compares those integers lexicographically.
Value
-  returns 0 if two version numbers are equal.
-  returns -1 if b is more recent. 
-  returns 1 if a is more recent.
 
See Also
Examples
compareVersion("2.0", "2.0-1")  # Returns  -1
compareVersion("2.0-5", "3.0") # Returns  -1
compareVersion("5.1-0","5.0-12")  # Returns 1
compareVersion("3.1-12","3.1-12")  # Returns 0
compareVersion("2.0", NA) # Returns 1
compareVersion(NA, "2.0-1") # Returns -1