iOS nsstring format retains the decimal point float double

self. Ordercost. Text = [nsstringstringwithformat:@ "%.1f yuan ",self. Order. Cost. Floatvalue];

%.1F represents a decimal point,%.2f represents a 2-bit decimal point, and so on

Format definition
The format specifiers supported by the NSString formatting methods and cfstring formatting functions follow the IEEE print f specification; The specifiers is summarized in Table 1. Note that you can also use the "n$" positional specifiers such as%[email protected]%2$s. For more details, see the IEEE printf specification. You can also use these format specifiers with the NSLog function.

Table 1 Format specifiers supported by the NSString formatting methods and cfstring formatting functions

Defined	Description
%@	Objective-c object, printed as the string returned by descriptionwithlocale:if available, or description otherwise. Also works with Cftyperef objects, returning the result of the Cfcopydescription function.
%%	'% ' character
%d,%d,%i	Signed 32-bit integer (int)
%u,%u	Unsigned 32-bit Integer (Unsigned int)
%hi	Signed 16-bit Integer (short)
%hu	Unsigned 16-bit Integer (Unsigned short)
%qi	Signed 64-bit Integer (Long Long)
%qu	Unsigned 64-bit Integer (Unsigned long Long)
%x	Unsigned 32-bit Integer (Unsigned int), printed in hexadecimal using the digits 0–9 and lowercase a–f
%x	Unsigned 32-bit Integer (Unsigned int), printed in hexadecimal using the digits 0–9 and uppercase A–F
%qx	Unsigned 64-bit Integer (Unsigned long Long), printed in hexadecimal using the digits 0–9 and lowercase a–f
%qx	Unsigned 64-bit Integer (Unsigned long Long), printed in hexadecimal using the digits 0–9 and uppercase A–F
%o,%o	Unsigned 32-bit Integer (Unsigned int), printed in octal
%f	64-bit floating-point number (double)
%e	64-bit floating-point number (double), printed in scientific notation using a lowercase e to introduce the exponent
%E	64-bit floating-point number (double), printed in scientific notation using a uppercase E to introduce the exponent
%g	64-bit floating-point number (double), printed in the style of%e if the exponent are less than–4 or greater than or equal To the precision, in the style of%f otherwise
%G	64-bit floating-point number (double), printed in the style of%E if the exponent are less than–4 or greater than or equal To the precision, in the style of%f otherwise
%c	8-bit unsigned character (unsigned char), printed by NSLog () as a ASCII character, or, if not a ASCII character, in the Octal format \\ddd or the Unicode hexadecimal format \\udddd, where D is a digit
%c	16-bit Unicode character (Unichar), printed by NSLog () as a ASCII character, or, if not a ASCII character, in the octal Format \\ddd or the Unicode hexadecimal format \\udddd, where D is a digit
%s	null-terminated array of 8-bit unsigned characters. %s interprets its input in the system encoding rather than, for example, UTF-8.
%s	null-terminated array of 16-bit Unicode characters
%p	void pointer (void *), printed in hexadecimal with the digits 0–9 and lowercase a–f, with a leading 0x
%l	Length modifier specifying a following a, a, E, E, F, F, g, or g conversion specifier applies to a long double argume Nt
%a	64-bit floating-point number (double), printed in scientific notation with a leading 0x and one hexadecimal digit before t He decimal point using a lowercase p to introduce the exponent
%A	64-bit floating-point number (double), printed in scientific notation with a leading 0X and one hexadecimal digit before t He decimal point using a uppercase P to introduce the exponent
%F	64-bit floating-point number (double), printed in decimal notation
%z	Length modifier specifying that a following d, I, O, U, x, or x conversion specifier applies to a size_t or the correspond ing signed integer type argument
%t	Length modifier specifying that a following d, I, O, U, x, or x conversion specifier applies to a ptrdiff_t or the Corresp onding unsigned integer type argument
%j	Length modifier specifying that a following d, I, O, U, x, or x conversion specifier applies to a intmax_t or uintmax_t ar Gument

Platform dependencies
Mac OS X uses several data types-nsinteger, Nsuinteger,cgfloat, and cfindex-to provide a consistent means of representing Values in 32-and 64-bit environments. In a 32-bit environment, Nsinteger and Nsuinteger is defined as int and unsigned int, respectively. In 64-bit environments, Nsinteger and Nsuinteger is defined as long and unsigned long, respectively. To avoid the need to use different Printf-style type specifiers depending on the platform, you can use the specifiers show N in Table 2. Note that in some cases your may has to cast the value.

Table 2 Format specifiers for data types

type	definition	recommendations
nsinteger	%ld or%lx	Cast The value to long
nsuinteger	%lu or%LX	Cast The value to unsigned long
cgfloat	%f or%g	%f works for floats and doubles when formatting; Warning when scanning
cfindex	%ld or%LX	the same as Nsinteger
pointer	%p	%p adds 0x to the beginning of the output. If you don ' t want the, use%LX and cast to long.
Long long	%lld or%llx	long Long is 64-bit on both 32-and 64-bit platforms
unsigned long long	%llu or%llx	unsigned long Long is 64-bit on both 32-and 64-bi T platforms

The following example illustrates the use of%LD to format an nsinteger and the use of a cast.

1 2	Nsinteger I = 42; printf("%ld\ n", (long) i);

In addition to the considerations mentioned in Table 2, there are one extra case with scanning:you must distinguish the Ty pes for float and double. You should the use%f for float, the%LF for double. If you need to use scanf (or a variant thereof) with CGFloat, switch to double instead, and copy the double to CGFloat.

1 2 3 4

CGFloat imagewidth; Double tmp; sscanf (str, "%LF", &tmp); ImageWidth = tmp;

It's important to remember,%LF does not represent cgfloat correctly on either 32-or 64-bit platforms. This is unlike%LD, which works for long in all cases.

iOS nsstring format retains the decimal point float double