PySerial Arduino receives data incorrectly - python-3.x

Question

The code that I've written is supposed to send the string "1" to the Arduino. Instead, from what I can see it receives "49" and for that reason both of the IF statements do not work. What am I doing wrong? I am using a Macbook(Mojave).
Here's the Arduino code:
String data;
void setup() {
Serial.begin(9600);
pinMode(13, OUTPUT);
Serial.println(1);
digitalWrite(13, LOW);
}
void loop() {
while (Serial.available()) {
data = Serial.read();
Serial.println(data);
if (data == "1") {
digitalWrite(LED_BUILTIN, HIGH);
Serial.println("ON");
} else if (data == "2") {
digitalWrite(LED_BUILTIN, LOW);
Serial.println("OFF");
}
}
}
And here's the python3 code:
import serial
import time
ArduinoSerial = serial.Serial('/dev/tty.usbserial-AH06F2WM', 9600)
time.sleep(2)
ArdData = ArduinoSerial.readline().decode('ascii')
print(ArdData)
ArduinoSerial.write("1".encode())
ArdData = ArduinoSerial.readline().decode('ascii')
print(ArdData)
Thank You!

Answer 1

In the ASCII table, a decimal value of 49 represents char '1'.
String and char are different. Serial.read() does not return a String. It returns an int.
You can use Serial.read() and treat a returned value as a char. Change String data to char data and compare against a char in the if statements.
char data; // char
void setup() {
Serial.begin(9600);
pinMode(13, OUTPUT);
Serial.println(1);
digitalWrite(13, LOW);
}
void loop() {
while (Serial.available()) {
data = Serial.read();
Serial.println(data);
if (data == '1') { // <- '1', not "1"
digitalWrite(LED_BUILTIN, HIGH);
Serial.println("ON");
} else if (data == '2') { // <- '2', not "2"
digitalWrite(LED_BUILTIN, LOW);
Serial.println("OFF");
}
}
}
Or, if you really want to use String, you should use Serial.readString() instead.
String data;
void setup() {
Serial.begin(9600);
pinMode(13, OUTPUT);
Serial.println(1);
digitalWrite(13, LOW);
}
void loop() {
while (Serial.available()) {
data = Serial.readString(); // <- readString() not read()
Serial.println(data);
if (data == "1") {
digitalWrite(LED_BUILTIN, HIGH);
Serial.println("ON");
} else if (data == "2") {
digitalWrite(LED_BUILTIN, LOW);
Serial.println("OFF");
}
}
}