当前位置:首页 > 开发 > 编程语言 > 编程 > 正文

使用NSString 的格式化大全

发表于: 2014-12-24   作者:dcj3sjt126com   来源:转载   浏览:
摘要: 格式定义The format specifiers supported by the NSString formatting methods and CFString formatting functions follow the IEEE printf specification; the specifiers are summarized in Table 1. Note that you c

格式定义
The format specifiers supported by the NSString formatting methods and CFString formatting functions follow the IEEE printf specification; the specifiers are summarized in Table 1. Note that you can also use the “n$” positional specifiers such as %1$@ %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
定义 说明
%@ 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 an uppercase E to introduce the exponent
%g 64-bit floating-point number (double), printed in the style of %e if the exponent is 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 is 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 an ASCII character, or, if not an 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 an ASCII character, or, if not an 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 that a following a, A, e, E, f, F, g, or G conversion specifier applies to a long double argument
%a 64-bit floating-point number (double), printed in scientific notation with a leading 0x and one hexadecimal digit before the 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 the 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 corresponding 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 corresponding 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 argument

平台依赖
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 are defined as int and unsigned int, respectively. In 64-bit environments, NSInteger and NSUInteger are 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 shown in Table 2. Note that in some cases you may have to cast the value.

Table 2 Format specifiers for data types
类型 定义 建议
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; but see below 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 that, 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-bit 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 is one extra case with scanning: you must distinguish the types for float and double. You should use %f for float, %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 is important to remember that %lf does not represent CGFloat correctly on either 32- or 64-bit platforms. This is unlike %ld, which works for long in all cases.

使用NSString 的格式化大全

  • 0

    开心

    开心

  • 0

    板砖

    板砖

  • 0

    感动

    感动

  • 0

    有用

    有用

  • 0

    疑问

    疑问

  • 0

    难过

    难过

  • 0

    无聊

    无聊

  • 0

    震惊

    震惊

编辑推荐
Objective-C是IOS开发的基本语言,用过OC的同学都知道,OC的方法名很长,但是表达的意思非常明确,
Objective-C 中核心处理字符串的类是 NSString 与 NSMutableString ,这两个类最大的区别就是NSStri
偶然发现了Dreamweaver的一个非常有用的功能,就是代码的格式化功能。一般情况下,我们写的html或者
@author YHC 以下示例格式化在easyui DataGrid 里的列数据,和使用自定义列formatter ,如果价格小于2
在日常工作中,总是感觉用PUTTY连接Linux一个窗口不够用,再开新的窗口又比较麻烦,于是想到是否可
目录 转自:http://blog.csdn.net/ghostyu/article/details/7091915 版本记录... 2 目录... 3 1 简
DataGridView控件使用大全:http://www.haogongju.net/art/847949 http://kb.cnblogs.com/a/2018504
转自:http://blog.csdn.net/ch_soft/article/details/6947695 UIScrollView 原理详解 ScrollView U
UIScrollView 原理详解 ScrollView UIScrollView UIScrollView为了显示多于一个屏幕的内容或者超过
对话框中我们常用了以下几种: 1、文件对话框(FileDialog) 它又常用到两个:    打开文件对话框(
版权所有 IT知识库 CopyRight © 2009-2015 IT知识库 IT610.com , All Rights Reserved. 京ICP备09083238号