diff --git a/API_Reference.py b/API_Reference.py
index 7f1e383..c29cdcc 100644
--- a/API_Reference.py
+++ b/API_Reference.py
@@ -290,6 +290,8 @@ x_array, y_array, matrix = guan.read_two_dimensional_data(filename='a', file_for
 
 x_array, y_array, matrix = guan.read_two_dimensional_complex_data(filename='a', file_format='.txt')
 
+guan.open_file(filename='a', file_format='.txt')
+
 guan.write_one_dimensional_data(x_array, y_array, filename='a', file_format='.txt')
 
 guan.write_one_dimensional_data_without_opening_file(x_array, y_array, file)
@@ -298,7 +300,11 @@ guan.write_two_dimensional_data(x_array, y_array, matrix, filename='a', file_for
 
 guan.write_two_dimensional_data_without_opening_file(x_array, y_array, matrix, file)
 
-guan.print_array(array, show_index=0, index_type=0)
+guan.write_two_dimensional_data_without_xy_array(matrix, filename='a', file_format='.txt')
+
+guan.write_two_dimensional_data_without_xy_array_and_without_opening_file(matrix, file)
+
+guan.print_array_with_index(array, show_index=1, index_type=0)
 
 
 
diff --git a/PyPI/setup.cfg b/PyPI/setup.cfg
index 3e2d489..20b5971 100644
--- a/PyPI/setup.cfg
+++ b/PyPI/setup.cfg
@@ -1,7 +1,7 @@
 [metadata]
 # replace with your username:
 name = guan
-version = 0.0.161
+version = 0.0.162
 author = guanjihuan
 author_email = guanjihuan@163.com
 description = An open source python package
diff --git a/PyPI/src/guan.egg-info/PKG-INFO b/PyPI/src/guan.egg-info/PKG-INFO
index 374c709..01ecdae 100644
--- a/PyPI/src/guan.egg-info/PKG-INFO
+++ b/PyPI/src/guan.egg-info/PKG-INFO
@@ -1,6 +1,6 @@
 Metadata-Version: 2.1
 Name: guan
-Version: 0.0.161
+Version: 0.0.162
 Summary: An open source python package
 Home-page: https://py.guanjihuan.com
 Author: guanjihuan
diff --git a/PyPI/src/guan/__init__.py b/PyPI/src/guan/__init__.py
index 566bdb6..5a91f9f 100644
--- a/PyPI/src/guan/__init__.py
+++ b/PyPI/src/guan/__init__.py
@@ -2,7 +2,7 @@
 
 # With this package, you can calculate band structures, density of states, quantum transport and topological invariant of tight-binding models by invoking the functions you need. Other frequently used functions are also integrated in this package, such as file reading/writing, figure plotting, data processing.
 
-# The current version is guan-0.0.161, updated on January 13, 2023.
+# The current version is guan-0.0.162, updated on February 20, 2023.
 
 # Installation: pip install --upgrade guan
 
@@ -2232,6 +2232,13 @@ def read_two_dimensional_complex_data(filename='a', file_format='.txt'):
                 matrix = np.append(matrix, [matrix_row], axis=0)
     return x_array, y_array, matrix
 
+def open_file(filename='a', file_format='.txt'):
+    try:
+        file = open(filename+file_format, 'a', encoding='UTF-8')
+    except:
+        file = open(filename+file_format, 'w', encoding='UTF-8')
+    return file
+
 def write_one_dimensional_data(x_array, y_array, filename='a', file_format='.txt'): 
     with open(filename+file_format, 'w') as file:
         guan.write_one_dimensional_data_without_opening_file(x_array, y_array, file)
@@ -2272,7 +2279,17 @@ def write_two_dimensional_data_without_opening_file(x_array, y_array, matrix, fi
         file.write('\n')
         i0 += 1
 
-def print_array(array, show_index=0, index_type=0):
+def write_two_dimensional_data_without_xy_array(matrix, filename='a', file_format='.txt'):
+    with open(filename+file_format, 'w') as file:
+        guan.write_two_dimensional_data_without_xy_array_and_without_opening_file(matrix, file)
+
+def write_two_dimensional_data_without_xy_array_and_without_opening_file(matrix, file):
+    for row in matrix:
+        for element in row:
+            file.write(str(element)+'   ')
+        file.write('\n')
+
+def print_array_with_index(array, show_index=1, index_type=0):
     if show_index==0:
         for i0 in array:
             print(i0)