Useful String Methods

This appendix contains a subset of useful String methods. (You do not have to import the String class because it is part of a special package that is always automatically imported.)

Selected Methods from the String Class:

public int length()
   Returns the length of this string.
     Returns:  the length of the sequence of characters represented by this object

public boolean isEmpty()
   Returns true if and only if length() is 0.
     Returns:  true if length() is 0, false otherwise

public boolean equals(Object anObject)
   Compares this string to the specified object.
     Parameters:  anObject - The object to compare this String against 
     Returns:  true if the given object represents a String equivalent to this string, 
     false otherwise

public boolean equalsIgnoreCase(String anotherString)
   Compares this String to another String, ignoring case considerations.
     Parameters:  anotherString - The String to compare this String against 
     Returns:  true if the argument is not null and it represents an equivalent String 
     ignoring case, false otherwise

public boolean contains(String str)
   Returns true if and only if this string contains the specified string.
     Parameters:  str - the String to search for
     Returns:  true if this string contains str, false otherwise

public boolean startsWith(String prefix)
   Tests if this string starts with the specified prefix.
     Parameters:  prefix - the prefix
     Returns:  true if prefix is a prefix of this string, false otherwise. Note also that 
     true will be returned if the argument is an empty string or is equal to this 
     String object as determined by the equals(Object) method.

public boolean endsWith(String suffix)
   Tests if this string ends with the specified suffix.
     Parameters:  suffix - the suffix
     Returns:  true if suffix is a suffix of this string, false otherwise. Note that the 
     result will be true if the argument is an empty string or is equal to this 
     String object as determined by the equals(Object) method.

public String toLowerCase()
   Converts all of the characters in this String to lower case.
     Returns:  the String, converted to lowercase

public String toUpperCase()
   Converts all of the characters in this String to upper case.
     Returns:  the String, converted to uppercase

public String concat(String str)
   Returns a new string representing this string followed by the specified string.  
   This string is unchanged.
     Parameters:  str - the String that is concatenated to the end of this String
     Returns:  the combined, concatenated string