Storing string from arduino to text file using python

I am using this code to send a string from arduino to PC

int i=0;
void setup(){  
  Serial.begin(9600);    // Open serial connection at a baud rate of 9600
  pinMode(13, OUTPUT);   //set pin13 in o/p mode
}

void loop(){ 
while(1)
{
Serial.write("10.028371,76.328873"); 
Serial.write('\0'); 
delay(1000);
  }
}

I need a python code that receives this string and store it in a text file as such.The arduino is transmitting this string continuously but i need it only once in the text file. I have written the below code but am getting only junk values in the text file

## import the serial library
import serial

## Boolean variable that will represent 
## whether or not the arduino is connected
connected = False

## establish connection to the serial port that your arduino 
## is connected to.

locations=['/dev/ttyUSB0','/dev/ttyUSB1','/dev/ttyUSB2','/dev/ttyUSB3']

for device in locations:
    try:
        print "Trying...",device
        ser = serial.Serial(device, 9600)
        break
    except:
        print "Failed to connect on",device

## loop until the arduino tells us it is ready
while not connected:
    serin = ser.read()
    connected = True

## open text file to store the current 
##gps co-ordinates received from the rover    
text_file = open("position4.txt", 'w')
## read serial data from arduino and 
## write it to the text file 'position.txt'
while ser.read():
    x=ser.read()
    print(x) 
    if x=="\0":
      text_file.seek(0)
      text_file.truncate()   
    text_file.write(x)
    text_file.flush()
## close the serial connection and text file
text_file.close()
ser.close()