如何从给定的file.txt中选择一个数组（列）？ （stringByAppendingPathComponent）Xcode

Question

我试图从包含数字数组的给定文件中选择一个数组（列），例如：

2012-09-02 16：27：15.010 SMA -0.818863 0.286575 0.206177 -0.108286 -0.231033 -0.303317

2012-09-02 16：27：15.017 SMA -1.024597 0.380875 0.456131 -0.282619 -0.123060 -0.048027

2012-09-02 16：27：15.023 SMA -0.754196 0.417053 1.165237 -0.010996 -0.078193 0.594972

2012-09-02 16：27：15.030 SMA -0.674835 0.486038 1.487640 0.061529 -0.008288 0.825637

这是我的代码，但它没有给出任何内容：

NSString* filePath = @"/Users/bahmadios/Documents/Xcode/selectArray/selectArray/Bus.txt";//file path...
NSString* fileRoot = [[NSBundle mainBundle]
                      pathForResource:filePath ofType:@"txt"];

// read everything from text
NSString* fileContents =
[NSString stringWithContentsOfFile:fileRoot
                          encoding:NSUTF8StringEncoding error:nil];

NSLog(@"%@", fileContents);

// first, separate by new line
NSArray* allLinedStrings =
[fileContents componentsSeparatedByCharactersInSet:
 [NSCharacterSet newlineCharacterSet]];
 NSLog(@"%@", allLinedStrings);
// then break down even further
NSString* strsInOneLine =
[allLinedStrings objectAtIndex:0];
NSLog(@"%@", strsInOneLine);

// choose whatever input identity you have decided. in this case ;

NSArray *array = [ strsInOneLine  componentsSeparatedByString:@" "];
if (array.count > 3) {
    NSLog(@"---- %@", array[3]);

我得到了：

2014-05-20 23:26:52.226 selectArray[5734:907] ---- (null)
2014-05-20 23:26:52.227 selectArray[5734:907] (null)
2014-05-20 23:26:52.228 selectArray[5734:907] (null)
2014-05-20 23:26:52.228 selectArray[5734:907] (null)
2014-05-20 23:26:52.229 selectArray[5734:907] ---- (null)

有什么问题？

Answer 1

我不确定您是否需要创建strsInOneLine的行。以下适用于我

NSString *filePath     = ...;
NSString *fileContents = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];

NSArray *lines = [fileContents componentsSeparatedByCharactersInSet:[NSCharacterSet newlineCharacterSet]];

[lines enumerateObjectsUsingBlock:^(NSString *line, NSUInteger idx, BOOL *stop) {
  NSArray *components = [line componentsSeparatedByString:@" "];
    if (components.count > 3) {
      NSLog(@"---- %@", components[3]);
    }
}];