python scripts changed to work with python 3

Author: kevin-pololu

pi/a_star.py

@@ -26,7 +26,7 @@ def read_unpack(self, address, size, format):
     return struct.unpack(format,bytes(bytearray(byte_list)))
 
   def write_pack(self, address, format, *data):
-    data_array = map(ord, list(struct.pack(format, *data)))
+    data_array = list(struct.pack(format, *data))
     self.bus.write_i2c_block_data(20, address, data_array)
     time.sleep(0.0001)
 

pi/benchmark.py

@@ -12,10 +12,10 @@
 total_time = timeit.timeit(a_star.test_write8, number=n)
 write_kbits_per_second = 8 * n * 8 / total_time / 1000
 
-print "Writes of 8 bytes: "+'%.1f'%write_kbits_per_second+" kilobits/second"
+print("Writes of 8 bytes: "+'%.1f'%write_kbits_per_second+" kilobits/second")
 
 n = 500
 total_time = timeit.timeit(a_star.test_read8, number=n)
 read_kbits_per_second = 8 * n * 8 / total_time / 1000
 
-print "Reads of 8 bytes: "+'%.1f'%read_kbits_per_second+" kilobits/second"
+print("Reads of 8 bytes: "+'%.1f'%read_kbits_per_second+" kilobits/second")

pi/heartbeat.py

@@ -2,14 +2,14 @@
 
 # Copyright Pololu Corporation.  For more information, see https://www.pololu.com/
 
-import urllib2
+import urllib.request
 import time
 
 while True:
   try:
     time.sleep(1)
-    urllib2.urlopen("http://localhost:5000/heartbeat/1").read()
+    urllib.request.urlopen("http://localhost:5000/heartbeat/1").read()
     time.sleep(0.01)
-    urllib2.urlopen("http://localhost:5000/heartbeat/0").read()
-  except urllib2.URLError:
+    urllib.request.urlopen("http://localhost:5000/heartbeat/0").read()
+  except urllib.request.URLError:
     print("error")