objective-c 从 NSString 的第一行删除换行符
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原文地址: http://stackoverflow.com/questions/1005281/
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Remove newline character from first line of NSString
提问by Brock Woolf
How can I remove the first \ncharacter from an NSString?
如何从 NSString 中删除第一个\n字符？
Edit: Just to clarify, what I would like to do is: If the first line of the string contains a \n character, delete it else do nothing.
编辑：只是为了澄清，我想做的是：如果字符串的第一行包含 \n 字符，则将其删除，否则什么都不做。
ie: If the string is like this:
即：如果字符串是这样的：
@"\nhello, this is the first line\nthis is the second line"
and opposed to a string that does not contain a newline in the first line:
与第一行不包含换行符的字符串相反：
@"hello, this is the first line\nthis is the second line."
I hope that makes it more clear.
我希望这能让它更清楚。
采纳答案by e.James
This should do the trick:
这应该可以解决问题：
NSString * ReplaceFirstNewLine(NSString * original)
{
NSMutableString * newString = [NSMutableString stringWithString:original];
NSRange foundRange = [original rangeOfString:@"\n"];
if (foundRange.location != NSNotFound)
{
[newString replaceCharactersInRange:foundRange
withString:@""];
}
return [[newString retain] autorelease];
}
回答by monowerker
[string stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]]
will trim your string from any kind of newlines, if that's what you want.
如果这是您想要的，将从任何类型的换行符中修剪您的字符串。
[string stringByReplacingOccurrencesOfString:@"\n" withString:@"" options:0 range:NSMakeRange(0, 1)]
will do exactly what you ask and remove newline if it's the first character in the string
如果它是字符串中的第一个字符，将完全按照您的要求执行并删除换行符
回答by Quinn Taylor
Rather than creating an NSMutableString and using a few retain/release calls, you can use only the original string and simplify the code by using the following instead: (requires 10.5+)
而不是创建一个 NSMutableString 并使用一些保留/释放调用，您可以只使用原始字符串并通过使用以下代码来简化代码：（需要 10.5+）
NSRange foundRange = [original rangeOfString:@"\n"];
if (foundRange.location != NSNotFound)
[original stringByReplacingOccurrencesOfString:@"\n"
withString:@""
options:0
range:foundRange];
(See -stringByReplacingOccurrencesOfString:withString:options:range:for details.)
（详情请参阅-stringByReplacingOccurrencesOfString:withString:options:range:。）
The result of the last call method call can even be safely assigned back to original IFyou autorelease what's there first so you don't leak the memory.
如果您首先自动释放那里的内容，则上次调用方法调用的结果甚至可以安全地分配回原始内容，这样您就不会泄漏内存。
