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Document that "#x" adds prefix "0x" and "#X" adds "0X". Addresses part of issue https://github.com/vitaut/format/issues/5

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Victor Zverovich 2013-11-16 21:06:07 -08:00
parent 2aa4cd9827
commit 0563aca180
1 changed files with 16 additions and 13 deletions
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doc/index.rst
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@ -115,7 +115,7 @@ The general form of a *standard format specifier* is:
sign: "+" | "-" | " "
width: `integer`
precision: `integer` | "{" `arg_index` "}"
type: "c" | "d" | "e" | "E" | "f" | "F" | "g" | "G" | "o" | "p" | s" | "x" | "X" | "b" | "B"
type: "b" | "c" | "d" | "e" | "E" | "f" | "F" | "g" | "G" | "o" | "p" | s" | "x" | "X"
The *fill* character can be any character other than '{' or '}'. The presence
of a fill character is signaled by the character following it, which must be
@ -167,9 +167,12 @@ following:
The ``'#'`` option causes the "alternate form" to be used for the
conversion. The alternate form is defined differently for different
types. This option is only valid for integer and floating-point types.
For integers, when octal, or hexadecimal, or binary output
is used, this option adds the prefix respective ``'0'``, or
``'0x'``, or ``'0b'`` to the output value. For floating-point numbers the
For integers, when binary, octal, or hexadecimal output is used, this
option adds the prefix respective ``"0b"`` (``"0B"``), ``"0"``, or
``"0x"`` (``"0X"``) to the output value. Whether the prefix is
lower-case or upper-case is determined by the case of the type
specifier, for example, the prefix ``"0x"`` is used for the type ``'x'``
and ``"0X"`` is used for ``'X'``. For floating-point numbers the
alternate form causes the result of the conversion to always contain a
decimal-point character, even if no digits follow it. Normally, a
decimal-point character appears in the result of these conversions
@ -225,21 +228,21 @@ The available integer presentation types are:
+---------+----------------------------------------------------------+
| Type | Meaning |
+=========+==========================================================+
| ``'b'`` | Binary format. Outputs the number in base 2. |
+---------+----------------------------------------------------------+
| ``'d'`` | Decimal integer. Outputs the number in base 10. |
+---------+----------------------------------------------------------+
| ``'o'`` | Octal format. Outputs the number in base 8. |
+---------+----------------------------------------------------------+
| ``'x'`` | Hex format. Outputs the number in base 16, using |
| | lower-case letters for the digits above 9. |
| | lower-case letters for the digits above 9. Using the |
| | ``'#'`` option with this type adds the prefix ``"0x"`` |
| | to the output value. |
+---------+----------------------------------------------------------+
| ``'X'`` | Hex format. Outputs the number in base 16, using |
| | upper-case letters for the digits above 9. |
+---------+----------------------------------------------------------+
| ``'b'`` | Binary format. Outputs the number in base 2, using |
| | a lower-case 0b if a prefix is requested. |
+---------+----------------------------------------------------------+
| ``'B'`` | Binary format. Outputs the number in base 2, using |
| | a upper-case 0B if a prefix is requested. |
| | upper-case letters for the digits above 9. Using the |
| | ``'#'`` option with this type adds the prefix ``"0X"`` |
| | to the output value. |
+---------+----------------------------------------------------------+
| none | The same as ``'d'``. |
+---------+----------------------------------------------------------+
@ -355,7 +358,7 @@ Replacing ``%+f``, ``%-f``, and ``% f`` and specifying a sign::
Format("{:-f}; {:-f}") << 3.14 << -3.14; // show only the minus -- same as '{:f}; {:f}'
// Result: "3.140000; -3.140000"
Replacing ``%x`` and ``%o`` and ``%b`` and converting the value to different bases::
Replacing ``%x`` and ``%o`` and converting the value to different bases::
Format("int: {0:d}; hex: {0:x}; oct: {0:o}; bin: {0:b}") << 42;
// Result: "int: 42; hex: 2a; oct: 52; bin: 101010"