OpenCV FileStorage读写.yml文件出现解析错误问题求助

First, let's break down why you're hitting that parsing error:

Your error Missing , between the elements happens because the YAML file generated by your write code has invalid formatting. Looking at your YAML snippet, you can see:

• The final score value is truncated (score:-1.095020413 instead of a complete number + closing })
• Manual concatenation of [, {:, and sequence closers leads to missing separators or unclosed mappings/sequences in nested layers
• OpenCV's YAML parser is strict about syntax, so even small formatting breaks will cause it to fail immediately (which is why your "Here" debug prints never run—FileStorage throws an error during initialization when it hits bad YAML).

Solution: Use OpenCV's Built-in Sequence/Map APIs #

Instead of manually writing YAML syntax characters like [ or {:, use OpenCV's beginWriteSeq()/endWriteSeq() and beginWriteMap()/endWriteMap() methods. These handle all formatting details (commas, brackets, closures) automatically, eliminating human error.

Fixed Write Code

if (saveLoad == MODEL::SAVE) {
    cv::FileStorage fs(detections_filename, cv::FileStorage::WRITE);
    
    // Start outer sequence for detections_structure
    cv::FileNode class_seq = fs.beginWriteSeq("detections_structure");
    
    for (auto &class_entry : dpm_detections) {
        // Create map for each class entry
        cv::FileNode class_map = fs.beginWriteMap();
        class_map["class_id"] = class_entry.first;
        
        // Start sequence for image paths under this class
        cv::FileNode img_seq = fs.beginWriteSeq("second");
        
        for (auto &img_entry : class_entry.second) {
            // Create map for image path entry
            cv::FileNode img_map = fs.beginWriteMap();
            img_map["img_path"] = img_entry.first;
            
            // Start sequence for detections under this image
            cv::FileNode det_seq = fs.beginWriteSeq("second");
            
            for (auto &detection : img_entry.second) {
                // Create map for individual detection
                cv::FileNode det_map = fs.beginWriteMap();
                det_map["classID"] = detection.classID;
                det_map["rect"] = detection.rect;
                det_map["score"] = detection.score;
                fs.endWriteMap(det_map);
            }
            
            fs.endWriteSeq(det_seq);
            fs.endWriteMap(img_map);
        }
        
        fs.endWriteSeq(img_seq);
        fs.endWriteMap(class_map);
    }
    
    fs.endWriteSeq(class_seq);
    fs.release();
}

Verification Steps #

1. Run the fixed write code to generate a new YAML file.
2. Open the YAML file to confirm:
   • All mappings {...} have closing }
   • Nested sequences are properly formatted with valid separators
   • No truncated values (like the incomplete score in your original snippet)
3. Test your existing read code again—it should now print your "Here" debug messages and successfully parse the file.

内容的提问来源于stack exchange，提问作者David W. Romero