Compares two strings lexicographically.
The comparison is based on the Unicode value of each character in
the strings. The character sequence represented by this
String
object is compared lexicographically to the
character sequence represented by the argument string. The result is
a negative integer if this String
object
lexicographically precedes the argument string. The result is a
positive integer if this String
object lexicographically
follows the argument string. The result is zero if the strings
are equal; compareTo
returns 0
exactly when
the equals(Object)
method would return true
.
This is the definition of lexicographic ordering. If two strings are
different, then either they have different characters at some index
that is a valid index for both strings, or their lengths are different,
or both. If they have different characters at one or more index
positions, let k be the smallest such index; then the string
whose character at position k has the smaller value, as
determined by using the < operator, lexicographically precedes the
other string. In this case, compareTo
returns the
difference of the two character values at position k
in
the two string -- that is, the value:
If there is no index position at which they differ, then the shorter string lexicographically precedes the longer string. In this case,this.charAt(k)-anotherString.charAt(k)
compareTo
returns the difference of the lengths of the
strings -- that is, the value:
this.length()-anotherString.length()
anotherString | the String to be compared. |
0
if the argument string is equal to
this string; a value less than 0
if this string
is lexicographically less than the string argument; and a
value greater than 0
if this string is
lexicographically greater than the string argument.
Diagram: String