Question

我正在使用NSScanner来解析逗号和行分隔的数据。实现起来相当简单，但我遇到了一个非常简单的问题。我想扫描下一行，即使它是空的。我现在遇到的问题是，如果有一个空行，它将跳过它并读取下一行。然后我的解析关闭，因为错误的数据最终在错误的地方。这是我现在的代码：

NSCharacterSet *setToIgnore = [NSCharacterSet characterSetWithCharactersInString:@",\r\n"];
[scanner setCharactersToBeSkipped:setToIgnore];

NSInteger levelID, campaignID;
NSString *title, *about, *gameBoard;
BOOL aTest = [scanner scanInteger:&levelID] && [scanner scanInteger:&campaignID];
aTest = [scanner scanUpToString:@"\r\n" intoString:&title];
aTest = [scanner scanUpToString:@"\r\n" intoString:&about];
aTest = [scanner scanUpToString:@"\r\n" intoString:&gameBoard];

所以数据格式如下： INT，INT 串串串

有时，第二个字符串（about）为空，NSScanner会跳过它并将gameBoard字符串读入about。如何告诉NSScanner在下一行读取？

Answer 1

解决方案1：删除setToIgnore语句并手动扫描分隔符：

NSInteger levelID, campaignID;
NSString *title, *about, *gameBoard;
BOOL aTest = [scanner scanInteger:&levelID]

[scanner setScanLocation:[scanner scanLocation]+1]; // skip comma
aTest=[scanner scanInteger:&campaignID];
[scanner setScanLocation:[scanner scanLocation]+2]; // skip line break
aTest = [scanner scanUpToString:@"\r\n" intoString:&title];
[scanner setScanLocation:[scanner scanLocation]+2]; // skip line break
aTest = [scanner scanUpToString:@"\r\n" intoString:&about];
[scanner setScanLocation:[scanner scanLocation]+2]; // skip line break
aTest = [scanner scanUpToString:@"\r\n" intoString:&gameBoard];
[scanner setScanLocation:[scanner scanLocation]+2]; // skip line break

解决方案2：用以下内容替换整批：

NSArray *lines=[file componentsSeparatedByString:@"\r\n"];

然后循环并分别解析这些行。

Answer 2

请勿忽略\r和\n。

NSScanner - 将下一行扫描到字符串中

2 个答案: