Use feature name in prediction (#988)

* add feature

* add label idx move func to .cpp file

* fix

* move func to predictor

* restore files

* fix by commits

* move the non-used features to the end of the feature vector

* fix by commits

* fix bug by commits

src/application/predictor.hpp

@@ -8,6 +8,7 @@
 
 #include <LightGBM/utils/openmp_wrapper.h>
 
+#include <map>
 #include <cstring>
 #include <cstdio>
 #include <vector>
@@ -128,12 +129,48 @@ public:
       Log::Fatal("Could not recognize the data format of data file %s.", data_filename);
     }
 
+    TextReader<data_size_t> predict_data_reader(data_filename, has_header);
+    std::unordered_map<int, int> feature_names_map_;
+    bool need_adjust = false;
+    if(has_header) {
+      std::string first_line = predict_data_reader.first_line();
+      std::vector<std::string> header = Common::Split(first_line.c_str(), "\t,");
+      header.erase(header.begin() + boosting_->LabelIdx());
+      for(int i = 0; i < static_cast<int>(header.size()); ++i) {
+        for(int j = 0; j < static_cast<int>(boosting_->FeatureNames().size()); ++j) {
+          if(header[i] == boosting_->FeatureNames()[j]) {
+            feature_names_map_[i] = j;
+            break;
+          }
+        }
+      }
+      for(auto s:feature_names_map_) {
+        if(s.first != s.second) {
+          need_adjust = true;
+          break;
+        }
+      }
+    }
     // function for parse data
     std::function<void(const char*, std::vector<std::pair<int, double>>*)> parser_fun;
     double tmp_label;
-    parser_fun = [this, &parser, &tmp_label]
+    parser_fun = [this, &parser, &tmp_label, &need_adjust, &feature_names_map_]
     (const char* buffer, std::vector<std::pair<int, double>>* feature) {
       parser->ParseOneLine(buffer, feature, &tmp_label);
+      if(need_adjust) {
+        int i = 0, j = static_cast<int>(feature->size());
+        while(i < j) {
+          if(feature_names_map_.find((*feature)[i].first) != feature_names_map_.end()) {
+            (*feature)[i].first = feature_names_map_[(*feature)[i].first];
+            ++i;
+          }
+          else {
+            //move the non-used features to the end of the feature vector
+            std::swap((*feature)[i], (*feature)[--j]);
+          }
+        }
+        feature->resize(i);
+      }
     };
 
     std::function<void(data_size_t, const std::vector<std::string>&)> process_fun =
@@ -160,7 +197,6 @@ public:
         fprintf(result_file, "%s\n", result_to_write[i].c_str());
       }
     };
-    TextReader<data_size_t> predict_data_reader(data_filename, has_header);
     predict_data_reader.ReadAllAndProcessParallel(process_fun);
     fclose(result_file);
   }