Java string format。 Formatter (Java Platform SE 7 )

Note: This method is locale sensitive, and may produce unexpected results if used for strings that are intended to be interpreted locale independently. To correct this problem, type something like this: System. The formatting of the sign is described in the. Conversion Specifier Applies To Description Example Code Output %a,%A Floating point The result is a hexadecimal representation of the floating point number String. If the conversion is 'a' or 'A', then the precision must not be specified. Below are some examples on how to convert float to String in Java using two decimal places. The substring of other to be compared begins at index ooffset and has length len. If the expression does not match any part of the input then the resulting array has just one element, namely this string. The result is zero if the strings are equal; compareTo returns 0 exactly when the method would return true. The rest of the parts are easy to understand. So as to simply fill in the blanks. This section is intended for users who want to get started quickly and are familiar with formatted printing in other programming languages. For example, the javac compiler may implement the operator with StringBuffer, StringBuilder, or java. This method may be used to trim from the beginning of a string. The index refers to char values Unicode code units and ranges from 0 to - 1. The offset argument is the index of the first character of the subarray and the count argument specifies the length of the subarray. Aug 20, 2015 , , comments Float is one of the most basic data type in Java for representing numerical values with decimal places. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. Andy Thomas-Cramer was kind enough to leave link in a comment below, which appears to point to the official spec. Prior to Java 5 java programmer relies on java. Returns: A copy of this string with leading and trailing white space removed, or this string if it has no leading or trailing white space. The syntax of this method is same in all classes: format String format, Object. Otherwise, the result is a string that represents the sign and magnitude absolute value of the argument. String literals are defined in section 3. Utilisé par Google Analytics pour calculer la durée d'une visite de site Web. Each byte in the subarray is converted to a char as specified in the method above. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. Returns: a string whose value is this string, with all leading and trailing space removed, or this string if it has no leading or trailing space. Any exception thrown by f will be propagated to the caller. The padding is on the left by default. Note that you can find all the details in the. For other values of ch, it is the largest value k such that: this. Flags, width, and precision are not applicable. In this case, compareTo returns the difference of the lengths of the strings -- that is, the value: this. Using formatting you could adjust the primitive data types to give results in your desired style. The offset argument is the index of the first character of the subarray. The above will print: The Time is 12. The precision of this value is limited by the resolution of the underlying operating system or hardware. If precision is specified then an will be thrown. Specified by: in interface Parameters: index - the index of the char value. If the precision is not specified, then it is assumed to be 6. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples. Limited formatting customization for arbitrary user types is provided through the interface. The '-' flag defined for applies. Whereas, f or the floating-point conversions the precision is the number of digits after the radix point. You need to remember these, if not all at least the important ones that you might need for your code. Die Absicht besteht darin, relevante und ansprechende Anzeigen für den einzelnen Nutzer anzuzeigen und somit für Publisher und Werbetreibende von Drittanbietern nützlicher zu sein. Note that this method does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The returned index is the smallest value k for which: this. Returns: the char value at the specified index of this string. Unless otherwise noted, methods for comparing Strings do not take locale into account. Width The width is the minimum number of characters to be written to the output. We can also create a Formatter instance, and use that to invoke the format method. Returns: true if the character sequence represented by the argument is a prefix of the substring of this object starting at index toffset; false otherwise. Index values refer to char code units, so a supplementary character uses two positions in a String. Using Formatter with Appendable Let's create a S tringBuilder instance sb, and create a Formatter using it. You do so with the help of format specifiers. Note that this Comparator does not take locale into account, and will result in an unsatisfactory ordering for certain locales. Used for analytics purposes to improve user experience. The problem that you're having is that both String. Trailing empty strings are therefore not included in the resulting array. Unpaired surrogates within the text range given by index and codePointOffset count as one code point each. The substring of this String object to be compared begins at index toffset and has length len. For full details, we strongly recommend you look at the Javadoc of. The first is the syntax for organizing the text, the second is the String object itself. Parameters: index - the index to the char values Returns: the code point value of the character at the index Throws: - if the index argument is negative or not less than the length of this string. The locale used is the one defined during the construction of this formatter. A line is either a sequence of zero or more characters followed by a line terminator, or it is a sequence of one or more characters followed by the end of the string. If the conversion is 'g' or 'G', then the precision is the total number of digits in the resulting magnitude after rounding. The required conversion is a character indicating content to be inserted in the output. In our example, the first format specifiers tm, indicates month formatted as two digits, te indicates the day of the month and tY indicated Year formatted as four digits. For specification of all possible formatting errors, see the section of the formatter class specification. Parameters: sb - The StringBuffer to compare this String against Returns: true if this String represents the same sequence of characters as the specified StringBuffer, false otherwise Since: 1. The first two are a little more standard and probably more easily maintainable. This value will be adjusted as necessary for Daylight Saving Time. If the width is not specified then there is no minimum. The following conversions may be applied to byte, , short, , int and , long, and. The location of the morning or afternoon marker '%Tp' may be locale-dependent. I Hour represented in 12 hour format, formatted as two digits with a leading zero as necessary, i. Returns: the number of Unicode code points in the specified text range Throws: - if the beginIndex is negative, or endIndex is larger than the length of this String, or beginIndex is larger than endIndex. You can simply use Formatter class that takes a StringBuilder instance as a parameter. Additional conversion types are provided to access Java-specific functionality e. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string. Date and Time Format Specifiers As implied from above date and time format specifiers are quite detailed. Parameters: ascii - The bytes to be converted to characters hibyte - The top 8 bits of each 16-bit Unicode code unit offset - The initial offset count - The length Throws: - If offset is negative, count is negative, or offset is greater than ascii. Otherwise, the result is obtained by invoking Integer. We specify the format string as the first argument to format. The implementation of string conversion is typically through the method toString, defined by Object and inherited by all classes in Java. Learn about string formatting in python? This method works as if by invoking the two-argument method with the given expression and a limit argument of zero. All literal strings and string-valued constant expressions are interned. Otherwise, the result is obtained by invoking Integer. For other values of ch, it is the smallest value k such that: this. Returns: the index of the first occurrence of the specified substring, starting at the specified index, or -1 if there is no such occurrence. Parameters: builder - A StringBuilder Since: 1. The result is a string that represents the sign and magnitude absolute value of the argument x. Also to provide a custom error messages on console. The eight high-order bits of each character are not copied and do not participate in the transfer in any way. Parameters: bytes - The bytes to be decoded into characters charset - The to be used to decode the bytes Since: 1. The behaviour on a null argument depends on the. Java String format The java string format method returns the formatted string by given locale, format and arguments. This method allows the application of a function to this string. Throws: - if beginIndex is negative or larger than the length of this String object. Case mapping is based on the Unicode Standard version specified by the class. Below are examples on how to convert double to String in Java using two decimal places. Returns: a string that has the same contents as this string, but is guaranteed to be from a pool of unique strings. Returns: the index of the last occurrence of the character in the character sequence represented by this object, or -1 if the character does not occur. If the limit n is greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater than n, and the array's last entry will contain all input beyond the last matched delimiter. This method returns an integer whose sign is that of calling compareTo with normalized versions of the strings where case differences have been eliminated by calling Character. The printf method is similar to C programming language printf method and allows a programmer to print formatting string directly to console, which makes System. If the precision is less than the number of digits which would appear after the decimal point in the string returned by or respectively, then the value will be rounded using the. Any surrogate pairs encountered in the sequence are combined as if by and the result is passed to the stream. The behavior of this method when this string cannot be encoded in the default charset is unspecified. An interpreter for printf-style format strings. The format method also uses locale for formatting a string. Parameters: count - number of times to repeat Returns: A string composed of this string repeated count times or the empty string if this string is empty or count is zero Throws: - if the count is negative. The String class has a format method in it which helps in formatting a string. 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. Returns: a new String that is composed of the elements separated by the delimiter Throws: - If delimiter or elements is null Since: 1. The optional flags is a set of characters that modify the output format. At tutorial 36-37 he starts using a String. This method always replaces malformed-input and unmappable-character sequences with this charset's default replacement byte array. If the '0' flag is given then the output will be padded with leading zeros to the field width following any indication of sign. Returns a formatted string using the specified format string and arguments. Otherwise, this String object is added to the pool and a reference to this String object is returned. The class should be used when more control over the encoding process is required. In this case, compareTo returns the difference of the two character values at position k in the two string -- that is, the value: this. It's a character indicating how the argument should be formatted. This conversion may be applied to char and. The comparison is based on the Unicode value of each character in the strings. The contents of the subarray are copied; subsequent modification of the character array does not affect the newly created string. The following conversion characters are used for formatting times: 'H' Hour of the day for the 24-hour clock, formatted as two digits with a leading zero as necessary i. Both take minimum two parameters, first of them is formatting instruction and other was actual String or anything which needs to be formatted. If the length of the argument string is 0, then this String object is returned. We will see how we can format numbers and dates. It is intended for users who want more precise specification of formatting behavior. Examples of locale-sensitive and 1:M case mappings are in the following table. If the precision is specified then an will be thrown. Let's see an example of using it with an Appendable. The argument list consists of all arguments passed to the method after the format string. If the precision is less than the number of digits to the right of the decimal point then the value will be rounded using the. To obtain correct results for locale insensitive strings, use toUpperCase Locale. How to Format a String in Java Up until now, we have seen up close, now it is time to understand how to format it. If a character with value ch occurs in the character sequence represented by this String object at an index no smaller than fromIndex, then the index of the first such occurrence is returned. If it is greater than the length of this string, it has the same effect as if it were equal to the length of this string: -1 is returned. The location of the morning or afternoon marker '%Tp' may be locale-dependent. The characters are copied into the subarray of dst starting at index dstBegin and ending at index: dstbegin + srcEnd-srcBegin - 1 Parameters: srcBegin - index of the first character in the string to copy. The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. More formatting flags are needed after this. For example, id 923 might be for males between 20 and 30 years old. If the char value specified at the given index is in the high-surrogate range, the following index is less than the length of this String, and the char value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. The precision is not applicable. However, if this is in a production program, I'd use the normal String concatenation operator, or a StringBuilder, as opposed to the String. It follows that for any two strings s and t, s. Also, Java formatting is more strict than C's; for example, if a conversion is incompatible with a flag, an exception will be thrown. Strings are constant; their values cannot be changed after they are created. The String class represents character strings. 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 method. This may be more than one 16-bit char in the case where the argument represents a supplementary character. String buffers support mutable strings. The String is searched backwards starting at the last character. Formatters are not necessarily safe for multithreaded access. It means that I need 10 blank spaces before the age. The length of the new String is a function of the charset, and hence may not be equal to the length of the subarray. Note that 'p' produces lower-case output. Integer and String Formatting That being said we can take a look at some String Format Java examples, to understand what is in store for us: What if we had an integer to address. Every method which produces formatted output requires a format string and an argument list. Parameters: str - the substring to search for. The hash value of the empty string is zero. Throws: - if offset is negative, or count is negative, or offset+count is larger than data. An index ranges from 0 to length - 1. You can experiment that to find out more yourself. The specific behavior depends on the conversion. This does not change this object's locale that was set during construction. This method may be used to trim space as defined above from the beginning and end of a string. I know Java %o byte, Byte, short, Short, int, Integer, long, Long and BigInteger Results in an octal integer String. Returns: the String, converted to uppercase. Throws: - if beginIndex or endIndex is negative, if endIndex is greater than length , or if beginIndex is greater than endIndex Since: 1. If the '-' flag is given, then the padding will be on the right. There is no restriction on the value of fromIndex. A String object is returned, representing the substring of this string that begins with the character at index k and ends with the character at index m-that is, the result of this. For finer-grained String comparison, refer to. These String format Java methods are so much less work. Any characters not explicitly defined as flags are illegal and are reserved for future extensions. Hours, 12-hour: The 12-hour clock requires the uppercase letter I in the format. A pool of strings, initially empty, is maintained privately by the class String. Format Specifier Data Type Output %a floating point except BigDecimal Returns Hex output of floating point number. IllegalFormatException : if format is illegal or incompatible. And the decimal digits are capped to two decimal places and rounding if necessary. Parameters: bytes - The bytes to be decoded into characters Since: 1. If the precision is not specified, then the default value is 6. Returns: a negative integer, zero, or a positive integer as the specified String is greater than, equal to, or less than this String, ignoring case considerations. When an uppercase specifier is used, then letters are shown in uppercase. JournalDev was founded by Pankaj Kumar in 2010 to share his experience and learnings with the whole world. The formatting of the magnitude m depends upon its value. Returns: a String that contains the characters of the character array. Obtaining a string from a string builder via the toString method is likely to run faster and is generally preferred. Throws: - if beginIndex or endIndex are negative, if endIndex is greater than length , or if beginIndex is greater than startIndex Since: 1. I have and found it hard to understand. If the char value at index - 1 is an unpaired low-surrogate or a high-surrogate, the surrogate value is returned. If the ' ' flag is given then the output will always begin with '0' prefix. For specification of all possible formatting errors, see the section of the formatter class specification. For that, you are supposed to use the negative value. The padding is on the left by default.。 。

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