MCP3008 TMP36 and LDR

from __future__ import print_function
import spidev
import time
import os

spi = spidev.SpiDev()
spi.open(0,0)

def get_adc(adcnum):
        r = spi.xfer2([1,(8+adcnum)<<4,0])
        adcout = ((r[1]&3) << 8) + r[2]
        return adcout

while True:
        get_adc(0) # throw away first reading as a test. didn't fix anything
        retrieve0 = get_adc(0) # get TMP36 #1
        time.sleep(1)
        get_adc(1) # throw away first reading as a test. didn't fix anything
        retrieve1 = get_adc(1) # get TMP36 #2
        time.sleep(1)
        get_adc(2) # throw away first reading as a test. didn't fix anything
        retrieve2 = get_adc(2) # get LDR #1 light level reading
        time.sleep(1)
        get_adc(3) # throw away first reading as a test. didn't fix anything
        retrieve3 = get_adc(3) # get LDR #2 light level reading
        time.sleep(1)

        #convert TMP36 #1 digital reading to Celsius temperature
        c_temp0 = (((retrieve0 * ( 3300.0 / 1024.0)) - 100.0) / 10.0) - 40.0
        c_temp0 = "%.1f" % c_temp0

        #convert TMP36 #2 digital reading to Celsius temperature
        c_temp1 = (((retrieve1 * ( 3300.0 / 1024.0)) - 100.0) / 10.0) - 40.0
        c_temp1 = "%.1f" % c_temp1

        print("TMP1:")
        print(retrieve0)
        print(c_temp0, "C")
        print("TMP2:")
        print(retrieve1)
        print(c_temp1, "C")
        print("LDR1:")
        print(retrieve2)
        print("LDR2:")
        print(retrieve3)
        time.sleep(0.5) # sleepy time...