elif using dictionary but without excecute the values

This question already has an answer here:

Replacements for switch statement in Python? 44 answers

---

def functionA(a1, a2, a3):
    results = {
        'case1': a2 / a3 if a3 != 0.0 else a2,
        'case2': 1,
        # ...
    }
    return results[a1]

However, I would advise against this approach as the entire dictionary has to be computed first only to pick up a single value.

Instead, if you really want to use dictionaries and have it also efficient, I would suggest:

myproc = {
    'case1': lambda a2, a3: a2 / a3 if a3 != 0.0 else a2,
    'case2': lambda a2, a3: 1
}

Then:

>>> myproc['case1'](2, 3)
0.6666666666666666

---

You can use ternary operator inside your dictionary

def functionA(a1, a2, a3):

    results = {
        'case1': a2 if a3==0 else a2/a3,
        'case2': 1
    }
    return results[a1]

Link : https://repl.it/NRkd

---

If it's just that one value, you can do it with a simple if-else.

def functionA(a1, a2, a3):

     if a3:
        case1_value = a2/a3
     else: 
        case1_value = a2

    results = {
        'case1': case1_value,
        'case2': 1,
        ...
    }
    return results[a1]

Or create a dvision function with this if-else condition and use it in your dict value.

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