Reading lists

[wirefree101]

I seek assistance with understanding how lists are accessed and their content stored. For this purpose I submit the following code snippet:

        ...
        ...
        to_gps = conn.makefile("r", 0) 
        msg = to_gps.readline()  
        if msg.startswith("$GPGGA"):  
                gps_data = msg.split(",")  
                lat = gps_data[2]  
		compassLat = gps_data[3]  
                lon = gps_data[4]  
		compassLon = gps_data[5]

A sample readline looks like the following:

$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47

My attempt to access the 3rd & 5th elements of this list generates a SyntaxError. Would greatly appreciate assistance with its resolution.

Best regards,
wirefree101

[wirefree101]

Would greatly appreciate assistance with identifying the source of the error. The presumed source of error is in the last 3 lines of the aforementioned code, which are stated below for quick reference:

compassLat = gps_data[3]  
lon = gps_data[4]  
compassLon = gps_data[5]

Best regards,
wirefree101

[bogdan.galiceanu]

Could you please post the entire error exactly as you get it, with the little arrow and everything?

[wirefree101]

Could you please post the entire error exactly as you get it, with the little arrow and everything?

As requested, I am providing the entire code below. Please refer to the while loop towards the end for the supposed source of error.

import appuifw, e32, key_codes, graphics, socket

BLACK = (0,0,0)

def draw_point():
    img.point((120,160), outline = YELLOW, width = 5)

def handle_redraw(rect):
    if img: canvas.blit(img)

def handle_event(event):
    ev = event['keycode']        
    
    if ev == key_codes.EKeyUpArrow:
        draw_point()
  
    handle_redraw(None)

def quit():
    app_lock.signal()

img = None
canvas = appuifw.Canvas(redraw_callback = handle_redraw, event_callback = handle_event)
appuifw.app.body = canvas
appuifw.app.screen = 'full'
appuifw.app.exit_key_handler = quit

w, h = canvas.size
img = graphics.Image.new((w, h))
img = graphics.Image.open("E:\\Images\\canvas.jpg")
canvas.blit(img)

address, services = socket.bt_discover()  
print "Discovered: %s, %s" % (address, services)  
target = (address, services.values()[0])  
conn = socket.socket(socket.AF_BT, socket.SOCK_STREAM)  
conn.connect(target)  
to_gps = conn.makefile("r", 0)

while True:  
        msg = to_gps.readline()  
        if msg.startswith("$GPGGA"):  
                gps_data = msg.split(",")  
                lat = gps_data[2]  
		#print lat
		lat_compass = gps_data[3]      #<-----------SyntaxError source
		#print lat_compass
                lon = gps_data[4]  
		#print lon
		lon_compass = gps_data[5]  
		#print lon_compass
                break
  
to_gps.close()  
conn.close()  
#print "You are now at latitude %s %s and longitude %s %s" % (lat, lat_compass, lon, lon_compass ) 



app_lock = e32.Ao_lock()
app_lock.wait()

[bogdan.galiceanu]

As requested, I am providing the entire code below.

I requested the error message exactly as it is displayed, not the code, because it might be easier and faster to help you that way (I for one don't have 2 devices handy to test the code and don't really know what it does).

[wirefree101]

I requested the error message exactly as it is displayed, not the code, because it might be easier and faster to help you that way (I for one don't have 2 devices handy to test the code and don't really know what it does).

Apologize for the overlook. Below is the precise error generated by the code above:

Traceback (most recent call last):
  File "C:\private\2000b1a5\default.py", line 81, in menu_action
    f()
  File "C:\private\2000b1a5\default.py", line 65, in query_and_exec
    execfile(script_list[index][1].encode('utf-8'), script_namespace.namespace)
  File "e:\python\graphics_gps_3.py", line 46
     lat_compass = gps_data[3]
     ^
 SyntaxError: invalid syntax

Look forward to a prompt response.

Best,
wirefree

[croozeus]

Appears to me as a small indent error on the line you pointed out. The indentation of the if block should be same. lat_compass = gps_data[3] is not properly indented.

This might have occured due to use of comments with the same indentation. Tip: Use comments after the code in the same line and not in a new line