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String line = …;
Scanner scanner = new Scanner(line);
Based on 53 examples
public final class Scanner extends Object implements Iterator
A simple text scanner which can parse primitive types and strings using regular expressions.
A Scanner
breaks its input into tokens using a
delimiter pattern, which by default matches whitespace. The resulting
tokens may then be converted into values of different types using the
various next methods.
For example, this code allows a user to read a number from System.in:
Scanner sc = new Scanner(System.in); int i = sc.nextInt();
As another example, this code allows long
types to be
assigned from entries in a file myNumbers
:
Scanner sc = new Scanner(new File("myNumbers")); while (sc.hasNextLong()) { long aLong = sc.nextLong(); }
The scanner can also use delimiters other than whitespace. This example reads several items in from a string:
String input = "1 fish 2 fish red fish blue fish"; Scanner s = new Scanner(input).useDelimiter("\\s*fish\\s*"); System.out.println(s.nextInt()); System.out.println(s.nextInt()); System.out.println(s.next()); System.out.println(s.next()); s.close();
prints the following output:
1 2 red blue
The same output can be generated with this code, which uses a regular expression to parse all four tokens at once:
String input = "1 fish 2 fish red fish blue fish"; Scanner s = new Scanner(input); s.findInLine("(\\d+) fish (\\d+) fish (\\w+) fish (\\w+)"); MatchResult result = s.match(); for (int i=1; i<=result.groupCount(); i++) System.out.println(result.group(i)); s.close();
The default whitespace delimiter used by a scanner is as recognized by {@link java.lang.Character}.{@link java.lang.Character#isWhitespace(char) isWhitespace}. The {@link #reset} method will reset the value of the scanner's delimiter to the default whitespace delimiter regardless of whether it was previously changed.
A scanning operation may block waiting for input.
The {@link #next} and {@link #hasNext} methods and their primitive-type companion methods (such as {@link #nextInt} and {@link #hasNextInt}) first skip any input that matches the delimiter pattern, and then attempt to return the next token. Both hasNext and next methods may block waiting for further input. Whether a hasNext method blocks has no connection to whether or not its associated next method will block.
The {@link #findInLine}, {@link #findWithinHorizon}, and {@link #skip} methods operate independently of the delimiter pattern. These methods will attempt to match the specified pattern with no regard to delimiters in the input and thus can be used in special circumstances where delimiters are not relevant. These methods may block waiting for more input.
When a scanner throws an {@link InputMismatchException}, the scanner will not pass the token that caused the exception, so that it may be retrieved or skipped via some other method.
Depending upon the type of delimiting pattern, empty tokens may be returned. For example, the pattern "\\s+" will return no empty tokens since it matches multiple instances of the delimiter. The delimiting pattern "\\s" could return empty tokens since it only passes one space at a time.
A scanner can read text from any object which implements the {@link java.lang.Readable} interface. If an invocation of the underlying readable's {@link java.lang.Readable#read} method throws an {@link java.io.IOException} then the scanner assumes that the end of the input has been reached. The most recent IOException thrown by the underlying readable can be retrieved via the {@link #ioException} method.
When a Scanner
is closed, it will close its input source
if the source implements the {@link java.io.Closeable} interface.
A Scanner
is not safe for multithreaded use without
external synchronization.
Unless otherwise mentioned, passing a null
parameter into
any method of a Scanner
will cause a
NullPointerException
to be thrown.
A scanner will default to interpreting numbers as decimal unless a
different radix has been set by using the {@link #useRadix} method. The
{@link #reset} method will reset the value of the scanner's radix to
An instance of this class is capable of scanning numbers in the standard
formats as well as in the formats of the scanner's locale. A scanner's
initial locale is the value returned by the {@link
java.util.Locale#getDefault} method; it may be changed via the {@link
#useLocale} method. The {@link #reset} method will reset the value of the
scanner's locale to the initial locale regardless of whether it was
previously changed.
The localized formats are defined in terms of the following parameters,
which for a particular locale are taken from that locale's {@link
java.text.DecimalFormat DecimalFormat} object, df, and its and
{@link java.text.DecimalFormatSymbols DecimalFormatSymbols} object,
dfs.
The strings that can be parsed as numbers by an instance of this class
are specified in terms of the following regular-expression grammar, where
Rmax is the highest digit in the radix being used (for example, Rmax is 9
in base 10).
10
regardless of whether it was previously changed.
Localized numbers
LocalGroupSeparator
The character used to separate thousands groups,
i.e., dfs.{@link
java.text.DecimalFormatSymbols#getGroupingSeparator
getGroupingSeparator()} LocalDecimalSeparator
The character used for the decimal point,
i.e., dfs.{@link
java.text.DecimalFormatSymbols#getDecimalSeparator
getDecimalSeparator()} LocalPositivePrefix
The string that appears before a positive number (may
be empty), i.e., df.{@link
java.text.DecimalFormat#getPositivePrefix
getPositivePrefix()} LocalPositiveSuffix
The string that appears after a positive number (may be
empty), i.e., df.{@link
java.text.DecimalFormat#getPositiveSuffix
getPositiveSuffix()} LocalNegativePrefix
The string that appears before a negative number (may
be empty), i.e., df.{@link
java.text.DecimalFormat#getNegativePrefix
getNegativePrefix()} LocalNegativeSuffix
The string that appears after a negative number (may be
empty), i.e., df.{@link
java.text.DecimalFormat#getNegativeSuffix
getNegativeSuffix()} LocalNaN
The string that represents not-a-number for
floating-point values,
i.e., dfs.{@link
java.text.DecimalFormatSymbols#getNaN
getNaN()} LocalInfinity
The string that represents infinity for floating-point
values, i.e., dfs.{@link
java.text.DecimalFormatSymbols#getInfinity
getInfinity()} Number syntax
NonASCIIDigit :: | = A non-ASCII character c for which {@link java.lang.Character#isDigit Character.isDigit}(c) returns true | ||||
Non0Digit :: | = [1-Rmax] | NonASCIIDigit | ||||
Digit :: | = [0-Rmax] | NonASCIIDigit | ||||
GroupedNumeral :: |
| ||||
Numeral :: | = ( ( Digit+ ) | GroupedNumeral ) | ||||
Integer :: | = ( [-+]? ( Numeral ) ) | ||||
| LocalPositivePrefix Numeral LocalPositiveSuffix | |||||
| LocalNegativePrefix Numeral LocalNegativeSuffix | |||||
DecimalNumeral :: | = Numeral | ||||
| Numeral LocalDecimalSeparator Digit* | |||||
| LocalDecimalSeparator Digit+ | |||||
Exponent :: | = ( [eE] [+-]? Digit+ ) | ||||
Decimal :: | = ( [-+]? DecimalNumeral Exponent? ) | ||||
| LocalPositivePrefix DecimalNumeral LocalPositiveSuffix Exponent? | |||||
| LocalNegativePrefix DecimalNumeral LocalNegativeSuffix Exponent? | |||||
HexFloat :: | = [-+]? 0[xX][0-9a-fA-F]*\.[0-9a-fA-F]+ ([pP][-+]?[0-9]+)? | ||||
NonNumber :: | = NaN | LocalNan | Infinity | LocalInfinity | ||||
SignedNonNumber :: | = ( [-+]? NonNumber ) | ||||
| LocalPositivePrefix NonNumber LocalPositiveSuffix | |||||
| LocalNegativePrefix NonNumber LocalNegativeSuffix | |||||
Float :: | = Decimal | ||||
| HexFloat | |||||
| SignedNonNumber |
Whitespace is not significant in the above regular expressions.
Constructor Summary | |
---|---|
Constructs a new Scanner that produces values scanned
from the specified file.
|
|
Constructs a new Scanner that produces values scanned
from the specified file.
|
|
Scanner(InputStream source) Constructs a new Scanner that produces values scanned
from the specified input stream.
|
|
Scanner(InputStream source, String charsetName) Constructs a new Scanner that produces values scanned
from the specified input stream.
|
|
Constructs a new Scanner that produces values scanned
from the specified source.
|
|
Scanner(ReadableByteChannel source) Constructs a new Scanner that produces values scanned
from the specified channel.
|
|
Scanner(ReadableByteChannel source, String charsetName) Constructs a new Scanner that produces values scanned
from the specified channel.
|
|
Constructs a new Scanner that produces values scanned
from the specified string.
|
Method Summary | |
---|---|
void |
close() Closes this scanner. |
Pattern |
Returns the Pattern this Scanner is currently
using to match delimiters.
|
String |
findInLine(Pattern pattern) Attempts to find the next occurrence of the specified pattern ignoring delimiters. |
String |
findInLine(String pattern) Attempts to find the next occurrence of a pattern constructed from the specified string, ignoring delimiters. |
String |
findWithinHorizon(Pattern pattern, int horizon) Attempts to find the next occurrence of the specified pattern. |
String |
findWithinHorizon(String pattern, int horizon) Attempts to find the next occurrence of a pattern constructed from the specified string, ignoring delimiters. |
boolean |
hasNext() Returns true if this scanner has another token in its input. |
boolean |
Returns true if the next complete token matches the specified pattern. |
boolean |
Returns true if the next token matches the pattern constructed from the specified string. |
boolean |
Returns true if the next token in this scanner's input can be interpreted as a BigDecimal using the
java.util.Scanner.nextBigDecimal method.
|
boolean |
Returns true if the next token in this scanner's input can be interpreted as a BigInteger in the default radix using the
java.util.Scanner.nextBigInteger method.
|
boolean |
hasNextBigInteger(int radix) Returns true if the next token in this scanner's input can be interpreted as a BigInteger in the specified radix using
the java.util.Scanner.nextBigInteger method.
|
boolean |
Returns true if the next token in this scanner's input can be interpreted as a boolean value using a case insensitive pattern created from the string "true|false". |
boolean |
Returns true if the next token in this scanner's input can be interpreted as a byte value in the default radix using the java.util.Scanner.nextByte method. |
boolean |
hasNextByte(int radix) Returns true if the next token in this scanner's input can be interpreted as a byte value in the specified radix using the java.util.Scanner.nextByte method. |
boolean |
Returns true if the next token in this scanner's input can be interpreted as a double value using the java.util.Scanner.nextDouble method. |
boolean |
Returns true if the next token in this scanner's input can be interpreted as a float value using the java.util.Scanner.nextFloat method. |
boolean |
Returns true if the next token in this scanner's input can be interpreted as an int value in the default radix using the java.util.Scanner.nextInt method. |
boolean |
hasNextInt(int radix) Returns true if the next token in this scanner's input can be interpreted as an int value in the specified radix using the java.util.Scanner.nextInt method. |
boolean |
Returns true if there is another line in the input of this scanner. |
boolean |
Returns true if the next token in this scanner's input can be interpreted as a long value in the default radix using the java.util.Scanner.nextLong method. |
boolean |
hasNextLong(int radix) Returns true if the next token in this scanner's input can be interpreted as a long value in the specified radix using the java.util.Scanner.nextLong method. |
boolean |
Returns true if the next token in this scanner's input can be interpreted as a short value in the default radix using the java.util.Scanner.nextShort method. |
boolean |
hasNextShort(int radix) Returns true if the next token in this scanner's input can be interpreted as a short value in the specified radix using the java.util.Scanner.nextShort method. |
IOException |
Returns the IOException last thrown by this
Scanner 's underlying Readable .
|
Locale |
locale() Returns this scanner's locale. |
MatchResult |
match() Returns the match result of the last scanning operation performed by this scanner. |
String |
next() Finds and returns the next complete token from this scanner. |
String |
Returns the next token if it matches the specified pattern. |
String |
Returns the next token if it matches the pattern constructed from the specified string. |
BigDecimal |
Scans the next token of the input as a java.math.BigDecimal. |
BigInteger |
Scans the next token of the input as a java.math.BigInteger. |
BigInteger |
nextBigInteger(int radix) Scans the next token of the input as a java.math.BigInteger. |
boolean |
Scans the next token of the input into a boolean value and returns that value. |
byte |
nextByte() Scans the next token of the input as a byte. |
byte |
nextByte(int radix) Scans the next token of the input as a byte. |
double |
Scans the next token of the input as a double. |
float |
Scans the next token of the input as a float. |
int |
nextInt() Scans the next token of the input as an int. |
int |
nextInt(int radix) Scans the next token of the input as an int. |
String |
nextLine() Advances this scanner past the current line and returns the input that was skipped. |
long |
nextLong() Scans the next token of the input as a long. |
long |
nextLong(int radix) Scans the next token of the input as a long. |
short |
Scans the next token of the input as a short. |
short |
nextShort(int radix) Scans the next token of the input as a short. |
int |
radix() Returns this scanner's default radix. |
void |
remove() The remove operation is not supported by this implementation of Iterator .
|
Scanner |
reset() Resets this scanner. |
Scanner |
Skips input that matches the specified pattern, ignoring delimiters. |
Scanner |
Skips input that matches a pattern constructed from the specified string. |
String |
toString() Returns the string representation of this Scanner .
|
Scanner |
useDelimiter(Pattern pattern) Sets this scanner's delimiting pattern to the specified pattern. |
Scanner |
useDelimiter(String pattern) Sets this scanner's delimiting pattern to a pattern constructed from the specified String .
|
Scanner |
Sets this scanner's locale to the specified locale. |
Scanner |
useRadix(int radix) Sets this scanner's default radix to the specified radix. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
---|
public Scanner(File source) throws FileNotFoundException
Scanner
that produces values scanned
from the specified file. Bytes from the file are converted into
characters using the underlying platform's
{@linkplain java.nio.charset.Charset#defaultCharset() default charset}.
source
- A file to be scannedFileNotFoundException
- if source is not foundpublic Scanner(File source, String charsetName) throws FileNotFoundException
Scanner
that produces values scanned
from the specified file. Bytes from the file are converted into
characters using the specified charset.
source
- A file to be scannedcharsetName
- The encoding type used to convert bytes from the file
into characters to be scannedFileNotFoundException
- if source is not foundpublic Scanner(InputStream source)
Scanner
that produces values scanned
from the specified input stream. Bytes from the stream are converted
into characters using the underlying platform's
{@linkplain java.nio.charset.Charset#defaultCharset() default charset}.
source
- An input stream to be scannedpublic Scanner(InputStream source, String charsetName)
Scanner
that produces values scanned
from the specified input stream. Bytes from the stream are converted
into characters using the specified charset.
source
- An input stream to be scannedcharsetName
- The encoding type used to convert bytes from the
stream into characters to be scannedpublic Scanner(Readable source)
Scanner
that produces values scanned
from the specified source.
source
- A character source implementing the {@link Readable}
interfacepublic Scanner(ReadableByteChannel source)
Scanner
that produces values scanned
from the specified channel. Bytes from the source are converted into
characters using the underlying platform's
{@linkplain java.nio.charset.Charset#defaultCharset() default charset}.
source
- A channel to scanpublic Scanner(ReadableByteChannel source, String charsetName)
Scanner
that produces values scanned
from the specified channel. Bytes from the source are converted into
characters using the specified charset.
source
- A channel to scancharsetName
- The encoding type used to convert bytes from the
channel into characters to be scannedpublic Scanner(String source)
Scanner
that produces values scanned
from the specified string.
source
- A string to scanMethod Detail |
---|
public void close()
If this scanner has not yet been closed then if its underlying {@linkplain java.lang.Readable readable} also implements the {@link java.io.Closeable} interface then the readable's close method will be invoked. If this scanner is already closed then invoking this method will have no effect.
Attempting to perform search operations after a scanner has been closed will result in an {@link IllegalStateException}.
public Pattern delimiter()
Pattern
this Scanner
is currently
using to match delimiters.
public String findInLine(Pattern pattern)
null
is returned and the scanner's
position is unchanged. This method may block waiting for input that
matches the pattern.
Since this method continues to search through the input looking for the specified pattern, it may buffer all of the input searching for the desired token if no line separators are present.
pattern
- the pattern to scan forpublic String findInLine(String pattern)
An invocation of this method of the form findInLine(pattern) behaves in exactly the same way as the invocation findInLine(Pattern.compile(pattern)).
pattern
- a string specifying the pattern to search forpublic String findWithinHorizon(Pattern pattern, int horizon)
This method searches through the input up to the specified search horizon, ignoring delimiters. If the pattern is found the scanner advances past the input that matched and returns the string that matched the pattern. If no such pattern is detected then the null is returned and the scanner's position remains unchanged. This method may block waiting for input that matches the pattern.
A scanner will never search more than horizon
code
points beyond its current position. Note that a match may be clipped
by the horizon; that is, an arbitrary match result may have been
different if the horizon had been larger. The scanner treats the
horizon as a transparent, non-anchoring bound (see {@link
Matcher#useTransparentBounds} and {@link Matcher#useAnchoringBounds}).
If horizon is 0
, then the horizon is ignored and
this method continues to search through the input looking for the
specified pattern without bound. In this case it may buffer all of
the input searching for the pattern.
If horizon is negative, then an IllegalArgumentException is thrown.
pattern
- the pattern to scan forhorizon
public String findWithinHorizon(String pattern, int horizon)
An invocation of this method of the form findWithinHorizon(pattern) behaves in exactly the same way as the invocation findWithinHorizon(Pattern.compile(pattern, horizon)).
pattern
- a string specifying the pattern to search forhorizon
public boolean hasNext()
public boolean hasNext(Pattern pattern)
pattern
- the pattern to scan forpublic boolean hasNext(String pattern)
An invocation of this method of the form hasNext(pattern) behaves in exactly the same way as the invocation hasNext(Pattern.compile(pattern)).
pattern
- a string specifying the pattern to scanpublic boolean hasNextBigDecimal()
BigDecimal
using the
{@link #nextBigDecimal} method. The scanner does not advance past any
input.
BigDecimal
public boolean hasNextBigInteger()
BigInteger
in the default radix using the
{@link #nextBigInteger} method. The scanner does not advance past any
input.
BigInteger
public boolean hasNextBigInteger(int radix)
BigInteger
in the specified radix using
the {@link #nextBigInteger} method. The scanner does not advance past
any input.
radix
- the radix used to interpret the token as an integerBigInteger
public boolean hasNextBoolean()
public boolean hasNextByte()
public boolean hasNextByte(int radix)
radix
- the radix used to interpret the token as a byte valuepublic boolean hasNextDouble()
public boolean hasNextFloat()
public boolean hasNextInt()
public boolean hasNextInt(int radix)
radix
- the radix used to interpret the token as an int valuepublic boolean hasNextLine()
public boolean hasNextLong()
public boolean hasNextLong(int radix)
radix
- the radix used to interpret the token as a long valuepublic boolean hasNextShort()
public boolean hasNextShort(int radix)
radix
- the radix used to interpret the token as a short valuepublic IOException ioException()
IOException
last thrown by this
Scanner
's underlying Readable
. This method
returns null
if no such exception exists.
public Locale locale()
A scanner's locale affects many elements of its default primitive matching regular expressions; see localized numbers above.
public MatchResult match()
IllegalStateException
if no match has been performed, or if the last match was
not successful.
The various next
methods of Scanner
make a match result available if they complete without throwing an
exception. For instance, after an invocation of the {@link #nextInt}
method that returned an int, this method returns a
MatchResult
for the search of the
Integer regular expression
defined above. Similarly the {@link #findInLine},
{@link #findWithinHorizon}, and {@link #skip} methods will make a
match available if they succeed.
public String next()
true
.
public String next(Pattern pattern)
true
.
If the match is successful, the scanner advances past the input that
matched the pattern.
pattern
- the pattern to scan forpublic String next(String pattern)
An invocation of this method of the form next(pattern) behaves in exactly the same way as the invocation next(Pattern.compile(pattern)).
pattern
- a string specifying the pattern to scanpublic BigDecimal nextBigDecimal()
If the next token matches the Decimal regular expression defined above then the token is converted into a BigDecimal value as if by removing all group separators, mapping non-ASCII digits into ASCII digits via the {@link Character#digit Character.digit}, and passing the resulting string to the {@link java.math.BigDecimal#BigDecimal(java.lang.String) BigDecimal(String)} constructor.
public BigInteger nextBigInteger()
An invocation of this method of the form
nextBigInteger() behaves in exactly the same way as the
invocation nextBigInteger(radix), where radix
is the default radix of this scanner.
public BigInteger nextBigInteger(int radix)
If the next token matches the Integer regular expression defined above then the token is converted into a BigInteger value as if by removing all group separators, mapping non-ASCII digits into ASCII digits via the {@link Character#digit Character.digit}, and passing the resulting string to the {@link java.math.BigInteger#BigInteger(java.lang.String) BigInteger(String, int)} constructor with the specified radix.
radix
- the radix used to interpret the tokenpublic boolean nextBoolean()
InputMismatchException
if the next token cannot be translated into a valid boolean value.
If the match is successful, the scanner advances past the input that
matched.
public byte nextByte()
An invocation of this method of the form
nextByte() behaves in exactly the same way as the
invocation nextByte(radix), where radix
is the default radix of this scanner.
public byte nextByte(int radix)
InputMismatchException
if the next token cannot be translated into a valid byte value as
described below. If the translation is successful, the scanner advances
past the input that matched.
If the next token matches the Integer regular expression defined above then the token is converted into a byte value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via {@link Character#digit Character.digit}, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to {@link Byte#parseByte(String, int) Byte.parseByte} with the specified radix.
radix
- the radix used to interpret the token as a byte valuepublic double nextDouble()
InputMismatchException
if the next token cannot be translated into a valid double value.
If the translation is successful, the scanner advances past the input
that matched.
If the next token matches the Float regular expression defined above then the token is converted into a double value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via {@link Character#digit Character.digit}, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to {@link Double#parseDouble Double.parseDouble}. If the token matches the localized NaN or infinity strings, then either "Nan" or "Infinity" is passed to {@link Double#parseDouble(String) Double.parseDouble} as appropriate.
public float nextFloat()
InputMismatchException
if the next token cannot be translated into a valid float value as
described below. If the translation is successful, the scanner advances
past the input that matched.
If the next token matches the Float regular expression defined above then the token is converted into a float value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via {@link Character#digit Character.digit}, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to {@link Float#parseFloat Float.parseFloat}. If the token matches the localized NaN or infinity strings, then either "Nan" or "Infinity" is passed to {@link Float#parseFloat(String) Float.parseFloat} as appropriate.
public int nextInt()
An invocation of this method of the form
nextInt() behaves in exactly the same way as the
invocation nextInt(radix), where radix
is the default radix of this scanner.
public int nextInt(int radix)
InputMismatchException
if the next token cannot be translated into a valid int value as
described below. If the translation is successful, the scanner advances
past the input that matched.
If the next token matches the Integer regular expression defined above then the token is converted into an int value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via {@link Character#digit Character.digit}, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to {@link Integer#parseInt(String, int) Integer.parseInt} with the specified radix.
radix
- the radix used to interpret the token as an int valuepublic String nextLine()
Since this method continues to search through the input looking for a line separator, it may buffer all of the input searching for the line to skip if no line separators are present.
public long nextLong()
An invocation of this method of the form
nextLong() behaves in exactly the same way as the
invocation nextLong(radix), where radix
is the default radix of this scanner.
public long nextLong(int radix)
InputMismatchException
if the next token cannot be translated into a valid long value as
described below. If the translation is successful, the scanner advances
past the input that matched.
If the next token matches the Integer regular expression defined above then the token is converted into a long value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via {@link Character#digit Character.digit}, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to {@link Long#parseLong(String, int) Long.parseLong} with the specified radix.
radix
- the radix used to interpret the token as an int valuepublic short nextShort()
An invocation of this method of the form
nextShort() behaves in exactly the same way as the
invocation nextShort(radix), where radix
is the default radix of this scanner.
public short nextShort(int radix)
InputMismatchException
if the next token cannot be translated into a valid short value as
described below. If the translation is successful, the scanner advances
past the input that matched.
If the next token matches the Integer regular expression defined above then the token is converted into a short value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via {@link Character#digit Character.digit}, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to {@link Short#parseShort(String, int) Short.parseShort} with the specified radix.
radix
- the radix used to interpret the token as a short valuepublic int radix()
A scanner's radix affects elements of its default number matching regular expressions; see localized numbers above.
public void remove()
Iterator
.
public Scanner reset()
Resetting a scanner discards all of its explicit state information which may have been changed by invocations of {@link #useDelimiter}, {@link #useLocale}, or {@link #useRadix}.
An invocation of this method of the form scanner.reset() behaves in exactly the same way as the invocation
scanner.useDelimiter("\\p{javaWhitespace}+") .useLocale(Locale.getDefault()) .useRadix(10);
public Scanner skip(Pattern pattern)
If a match to the specified pattern is not found at the current position, then no input is skipped and a NoSuchElementException is thrown.
Since this method seeks to match the specified pattern starting at the scanner's current position, patterns that can match a lot of input (".*", for example) may cause the scanner to buffer a large amount of input.
Note that it is possible to skip something without risking a
NoSuchElementException
by using a pattern that can
match nothing, e.g., sc.skip("[ \t]*")
.
pattern
- a string specifying the pattern to skip overpublic Scanner skip(String pattern)
An invocation of this method of the form skip(pattern) behaves in exactly the same way as the invocation skip(Pattern.compile(pattern)).
pattern
- a string specifying the pattern to skip overpublic String toString()
Returns the string representation of this Scanner
. The
string representation of a Scanner
contains information
that may be useful for debugging. The exact format is unspecified.
toString
in class Object
public Scanner useDelimiter(Pattern pattern)
pattern
- A delimiting patternpublic Scanner useDelimiter(String pattern)
String
.
An invocation of this method of the form useDelimiter(pattern) behaves in exactly the same way as the invocation useDelimiter(Pattern.compile(pattern)).
Invoking the {@link #reset} method will set the scanner's delimiter to the default.
pattern
- A string specifying a delimiting patternpublic Scanner useLocale(Locale locale)
A scanner's locale affects many elements of its default primitive matching regular expressions; see localized numbers above.
Invoking the {@link #reset} method will set the scanner's locale to the initial locale.
locale
- A string specifying the locale to usepublic Scanner useRadix(int radix)
A scanner's radix affects elements of its default number matching regular expressions; see localized numbers above.
If the radix is less than Character.MIN_RADIX
or greater than Character.MAX_RADIX
, then an
IllegalArgumentException
is thrown.
Invoking the {@link #reset} method will set the scanner's radix to
10
.
radix
- The radix to use when scanning numbers
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