Undefined function error

Python Help
1

i’m confused why my “SaveLog” function works in all IF statements, but gives me a “SaveLog was not defined” error in the first IF statement “if firstBoot”.? if i comment out the SaveLog, the rest of the if statement works fine.

import serial
import time
from datetime import datetime
import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BCM)
GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP)
SP2 = serial.Serial( "/dev/ttyS0", baudrate=115200)#PC

firstBoot=True

MSG=""
S1Timer= 0
Save =""

while True:
    now = datetime.now()
    CT = now.strftime("%H:%M %m/%d")
    Mili =time.perf_counter()

    if  firstBoot:
        Save="boot log,"
        SaveLog()
        print("first boot")
        firstBoot=False

    #GPIO input S1

    if not GPIO.input(23) and Mili  > S1Timer + 5:
        S1Timer= Mili
        #time.sleep(.2)
        Save="S1"
        SaveLog()
        print("S1 Triggered...")

    #in from PC
    if (SP2.inWaiting() > 0):

        PcIN = SP2.readline().decode()
        time.sleep(1)
        print(PcIN, end='')
        pcout= PcIN.strip()

        if pcout=="log":
            print("")

            Sender()

    def SaveLog():
        LOG = open("LOG.txt" , "a",buffering=1 )
        LOG.write(Save+",")
        time.sleep(.1)
        LOG.close
        #print(Save)

    def Sender():

        with open('LOG.txt', 'r') as file:
            LogFile = file.read()
            #LogOut= LogFile.strip()

        SP2.write(str.encode(LogFile +"\n"))
        print(LogFile)
2

Move SaveLog to the start of your code, before the while loop. Functions have to be defined before you can call them:

import serial
...

def SaveLog():
    ...

while True:
    ...
3

Thank you, any idea why the If statement under it DOES work without moving the function?

4

Because it is under the function definition.

Python executes code from the top of the file down to the end, and that includes function definitions:

# No functions exist yet (except built-in functions).

# This defines the first function.
def first():
    return "This is first"

print(first())   # Okay, because first exists.
print(second())  # NOT OKAY, because second doesn't exist **yet**.

# This defines the second function.
def second():
    return "And this is second"

If you copy that code and run it, you will see that “This is first” is printed and then you will get a NameError that second doesn’t exist.

But if you move the second print to the very end, after the second function definition, it will be fine.

(Note: if you do copy the code, be careful because the Discuss software may change quotation marks to curly quotes, and you will need to change them back.)