如何使用 NSScanner? [英] How to use NSScanner?

问题描述

我刚刚阅读了 Apple 文档.我正在尝试获取此字符串的整数:

I've just read Apple documentation for NSScanner. I'm trying to get the integer of this string:

@"user logged (3 attempts)"

我找不到任何示例，如何在括号内扫描.有什么想法吗?

I can't find any example, how to scan within parentheses. Any ideas?

代码如下:

NSString *logString = @"user logged (3 attempts)";
NSScanner *aScanner = [NSScanner scannerWithString:logString];

[aScanner scanInteger:anInteger];

NSLog(@"Attempts: %i", anInteger);

推荐答案

`这是我从字符串中获取某些值的方法

`Here is what I do to get certain values out of a string

首先我定义了这个方法

- (NSString *)getDataBetweenFromString:(NSString *)data leftString:(NSString *)leftData rightString:(NSString *)rightData leftOffset:(NSInteger)leftPos; 
{         
    NSInteger left, right;         
    NSString *foundData;
    NSScanner *scanner=[NSScanner scannerWithString:data];                  
    [scanner scanUpToString:leftData intoString: nil];         
    left = [scanner scanLocation];         
    [scanner setScanLocation:left + leftPos];         
    [scanner scanUpToString:rightData intoString: nil];         
    right = [scanner scanLocation] + 1;         
    left += leftPos;         
    foundData = [data substringWithRange: NSMakeRange(left, (right - left) - 1)];         return foundData; 
}

然后调用它.

foundData = [self getDataBetweenFromString:data leftString:@"user logged (" rightString:@"attempts)" leftOffset:13];

leftOffset 是左边字符串的字符数

leftOffset is the number of characters for the left string

可能是一种更简单的清洁方法，但这是我的解决方案.

Could be an easier cleaner way but that was my solution.

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