String.compareTo()
Signature
int compareTo (String s1, String s2)
Description
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 the String s1
lexicographically precedes the
String s2
. The result is a positive integer if the String s1
lexicographically follows the string s2
. 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:
s1.charAt (k) - s2.charAt (k)
If there is no index position at which they differ, then the shorter
string lexicographically precedes the longer string. In this case,
compareTo returns the difference of the lengths of the strings -- that is, the value:
s1.length () - s2.length ()
Parameters
Name | Type | Description |
s1 | String | A String to compare. |
s2 | String | A second String to compare. |
Returns
Type | Description |
int | A negative integer, zero, or a positive integer as s1 is
greater than, equal to, or less than s2. |
Example
int result = String.compareTo ("This is a test", "This is a tesq");
Result is:
result contains: -1