diff --git a/NPYViewer.py b/NPYViewer.py
index 00de345..8d826fb 100644
--- a/NPYViewer.py
+++ b/NPYViewer.py
@@ -19,26 +19,10 @@
 
 version="1.28"
 
-def isint(s):
-    try:
-        print(int(s))
-        return True
-    except ValueError:
-        return False
-
-
-def isfloat(s):
-    try:
-        print(float(s))
-        return True
-    except ValueError:
-        return False
-
-
 
 def openNPY_CLI_noGUI (filename):
 
-        if ".npy" in filename:
+        if Path(filename).suffix.lower() == ".npy":
             data = np.load(filename, allow_pickle=True)
         else:
             data = np.array(pd.read_csv(filename).values.tolist())
@@ -83,7 +67,8 @@ def saveAs(self):
             self, 'Save File', home, 'NPY (*.npy);;CSV(*.csv);;MAT(*.mat)')[0]
         # path = QFileDialog.getSaveFileName(
         #    self, 'Save File', home, 'CSV(*.csv)')[0]
-        if path != "" and ".csv" in path:
+        suffix = Path(path).suffix.lower()
+        if path != "" and suffix == ".csv":
             with open((path.replace(".csv", "") + ".csv"), 'w') as stream:
                 writer = csv.writer(stream)
                 for row in range(self.tableWidget.rowCount()):
@@ -109,9 +94,9 @@ def saveAs(self):
                 if rowdata != []:
                     OutMatrix.append(rowdata)
             OutMatrix = np.array(OutMatrix)
-            if ".csv" in path:
+            if suffix == ".npy":
                 np.save(path, np.array(OutMatrix))
-            if ".mat" in path:
+            if suffix == ".mat":
                 mdic = {"ans": OutMatrix}
                 print(OutMatrix)
                 savemat(path, mdic)
@@ -127,7 +112,7 @@ def openNPY(self):
         filename = QFileDialog.getOpenFileName(self, 'Open .NPY file', home, ".NPY files (*.npy);;.CSV files (*.csv)")[
             0]
         if filename != "":
-            if ".npy" in filename:
+            if Path(filename).suffix.lower() == ".npy":
                 data = np.load(filename, allow_pickle=True)
             else:
                 data = np.array(pd.read_csv(filename).values.tolist())
@@ -168,7 +153,7 @@ def openNPY(self):
 
     def openNPY_CLI(self,filename):
 
-            if ".npy" in filename:
+            if Path(filename).suffix.lower() == ".npy":
                 data = np.load(filename, allow_pickle=True)
             else:
                 data = np.array(pd.read_csv(filename).values.tolist())
@@ -246,7 +231,7 @@ def createMenu(self):
         self.statusBar()
 
         ViewTimeSeriesAct= QAction(QIcon(None), 'View as &Time Series', self)
-        ViewTimeSeriesAct.setShortcut('Ctrl+S')
+        ViewTimeSeriesAct.setShortcut('Ctrl+T')
         ViewTimeSeriesAct.setStatusTip('View as TimeSeries')
         ViewTimeSeriesAct.triggered.connect(self.ViewTimeseries)
         self.statusBar()