How to avoid ifs for every command?

Question

I am building a virtual assistant for myself and it feels wrong and ineffective to ask for every command by an individual if like here as example:

WAKE = 'hello'


while True:
    print("Mic ready")
    text = voice.get_audio()
    if WAKE in text:
        if "note" in text:
            voice.speak("What do you want to note?")
            print("What do you want to note?")
            text = voice.get_audio()
            Vcm.note(text)
        else if "timer" in text:
            voice.speak("How long is that timer supposed to run?")
            print("How long is that timer supposed to run?")
            text = voice.get_audio()
            Vcm.timer(text)
        else:
            voice.speak("At your service")
            print("At your service")
            text = voice.get_audio()

Isn't there an more efficient way to check which command to execute?

Welcome to Stack Overflow! If the code works and you're looking for advice on improving it, [codereview.se] is the appropriate place. But see https://codereview.meta.stackexchange.com/questions/5777/a-guide-to-code-review-for-stack-overflow-users first. — Barmar, Aug 06 '21 at 15:50
Use a data-driven approach. Create a dictionary that maps words to search for in the input to functions to call. Then loop over the dictionary and call the corresponding function when it matches. — Barmar, Aug 06 '21 at 15:50
Python 3.10.xx now has a switch/case block: https://stackoverflow.com/a/66877137/421195 — paulsm4, Aug 06 '21 at 15:55

score 4 · Accepted Answer · 2021-08-06T19:47:36.210

4

You could separate your commands into functions:

def note():
    #note body

def timer():
    #timer body

def default():
    #default body

Then wrap your commands in a dictionary:

commands = {
    'note': lambda: note(),
    'timer': lambda: timer()
}

and define default separately:

default_command = lambda: default()

Then you can check what is in text:

for word in text:
   command = commands.get(word, None)
   if command not None:
       command()
       break
else:
    default_command()

Not sure this is what you wanted, but it may make your code more sparse if you have many commands.

EDIT:

According to Can a lambda function have a bool value of false?, lambda expressions act 'truthy'. So you could simplify the last bit too!

for word in text:
    command = commands.get(word, None)
    if command:
        command()
        break
else:
    default_command()

edited Aug 06 '21 at 19:47

answered Aug 06 '21 at 15:55

Thanks, I'll try it out! – Havelex Aug 06 '21 at 18:35
Good idea, however, since text is a string, word doesn't go through every word like "Hello" then "make", but it goes through every letter one by one: "H", "e", "l" etc. Therefor no command will ever be executed- – Havelex Aug 06 '21 at 18:54
Btw, the code above and the function declaration are in different files – Havelex Aug 06 '21 at 19:05
I fixed the word problem, but then when "command()" gets called it tells me that I miss a parameter for "note()", which i do, but when I change "command()" to "command(text)" it gives me an error of too many arguments – Havelex Aug 06 '21 at 19:14
Split the text on spaces using the .split() method. Find usage under the strings section of the docs: https://docs.python.org/3/library/stdtypes.html#str – Aug 06 '21 at 19:31
1

I apologize, this one is on me, it took me 10 seconds of a youtube video to find a solution! Still thank you for the Idea – Havelex Aug 06 '21 at 19:42
@Havelex, no worries! If you're happy with solution mark it as the best fit! Glad I could help :) – Aug 06 '21 at 19:45

score 1 · Answer 2 · answered Aug 06 '21 at 19:44

while True:
    print("Mic ready")
    text = voice.get_audio()
    if WAKE in text:
        words = text.split(" ")
        for word in words:
            command = commands.get(word)
            if command:
                command(text)
                break
        else:
            vcm.default()
    ```

commands = {
'note': lambda text: note(text)

}

How to avoid ifs for every command?

2 Answers2