Fix subscript

Sources/CSV+iterator.swift

@@ -66,6 +66,9 @@ extension CSV {
             guard let index = headerRow!.index(of: key) else {
                 return nil
             }
+            guard (data.startIndex ..< data.endIndex).contains(index) else {
+                return nil
+            }
             return data[index]
         }
 
@@ -79,7 +82,9 @@ extension CSV {
             assert(headerRow != nil, "CSVConfiguration.hasHeaderRow must be true")
             var dictionary: [String : String] = [:]
             for (key, value) in zip(headerRow!, data) {
-                dictionary[key] = value
+                if !dictionary.keys.contains(key) {
+                    dictionary[key] = value
+                }
             }
             return dictionary
         }

Tests/CSV/CSVTests.swift

@@ -155,7 +155,7 @@ class CSVTests: XCTestCase {
         }
     }
 
-    func testSubscriptString() {
+    func testSubscriptString1() {
         let csvString = "key1,key2\nvalue1,value2"
         let config = CSVConfiguration(hasHeaderRow: true)
         let csv = try! CSV(string: csvString, config: config)
@@ -166,6 +166,17 @@ class CSVTests: XCTestCase {
         }
     }
 
+    func testSubscriptString2() {
+        let csvString = "key1,key2\nvalue1"
+        let config = CSVConfiguration(hasHeaderRow: true)
+        let csv = try! CSV(string: csvString, config: config)
+        for row in csv {
+            XCTAssertEqual(row["key1"], "value1")
+            XCTAssertNil(row["key2"])
+            XCTAssertNil(row["key9"])
+        }
+    }
+
     func testToArray() {
         let csvString = "1,2,3,4,5\n6,7,8,9,0"
         let csv = try! CSV(string: csvString)
@@ -174,7 +185,7 @@ class CSVTests: XCTestCase {
         XCTAssertEqual(rows[1], ["6", "7", "8", "9", "0"])
     }
 
-    func testToDictionary() {
+    func testToDictionary1() {
         let csvString = "id,name\n1,name1\n2,name2"
         let config = CSVConfiguration(hasHeaderRow: true)
         let csv = try! CSV(string: csvString, config: config)
@@ -187,4 +198,17 @@ class CSVTests: XCTestCase {
         XCTAssertNil(rows[1]["yyy"])
     }
 
+    func testToDictionary2() {
+        let csvString = "id,name,id\n1,name1,11\n2,name2,22"
+        let config = CSVConfiguration(hasHeaderRow: true)
+        let csv = try! CSV(string: csvString, config: config)
+        let rows = csv.map { $0.toDictionary() }
+        XCTAssertEqual(rows[0]["id"], "1")
+        XCTAssertEqual(rows[0]["name"], "name1")
+        XCTAssertNil(rows[0]["xxx"])
+        XCTAssertEqual(rows[1]["id"], "2")
+        XCTAssertEqual(rows[1]["name"], "name2")
+        XCTAssertNil(rows[1]["yyy"])
+    }
+
 }