add method Reader\AbstractReader::firstColumns

README.md

@@ -21,4 +21,8 @@ Because of using Generator for iterate over input file's rows. **DO NOT BREAK**
   print_r($rows);
   }
 
+  // if we interest only first column of each row then
+  foreach ($easy->firstColumns() as $str) {
+  echo $str . PHP_EOL;
+  }
  ?>

src/Reader/AbstractReader.php

@@ -32,4 +32,14 @@ public function count (): int
 
  return $this->count_rows;
  }
+
+ /**
+ * @throws ReaderException
+ */
+ public function firstColumns (): Generator
+ {
+ foreach ($this->rows() as $row) {
+ yield $row[0];
+ }
+ }
 }