python split string and pick substring
I am having a lot of trouble with the list returned by the split function in python. I am probably being incredibly dense.
My python code is as follows
str = "XXX:YYY:ZZZ"
var+=1
ins = str.split(':')
print ins
When the script runs it returns the following result
['XXX','YYY','ZZZ']
What i am struggling to do is pull out the string contained the second string in the list. I would have thought the following code at the end of the python code would work.
print ins[1]
but when i run it i get the following error
IndexError: list index out of range
Any help would be much appreciated
full code
import time
ser = serial.Serial("COM3", 9600)
print ser
time.sleep(3)
print "Sending serial data"
var = 0
while var<=10:
str = ser.readline()
print str
var+=1
ins = str.split(':')
print ins
print ins[0]
if (str.split(':')=='end\n'):
break
if(ser.isOpen()):
print "Serial connection is still open."
ser.close();
print "Serial connectionnow terminated."
This returns
Serial<id=0x2a7fc50, open=True>(port='COM3', baudrate=9600, bytesize=8, parity='N', stopbits=1, timeout=None, xonxoff=False, rtscts=False, dsrdtr=False)
Sending serial data
Program Initiated
['Program Initiated\n']
Program开发者_开发技巧 Initiated
0:addsd:1
['0', 'addsd', '1\n']
0
1:addsd:2
['1', 'addsd', '2\n']
1
2:end:2
['2', 'end', '2\n']
2
Your code will not work in instances where the input you're analyzing has a length <= 1.
Try checking for that and handling it in your code.
One of the lines you are reading probably has a two '\n' characters in a row. When that string is read with readlines() and then spit it has no [1] index only a [0] index.
What output do you get for the program:
import serial // Or is serial a builtin for the version of python you are using?
print repr(serial.Serial("COM3", 9600))
Thanks, Marlen
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