Python switch statement

通过 dict 及其 get(key[, default]) 方法实现。

def f(x):
    return {
        'a': 1,
        'b': 2
    }.get(x, 9)  # 9 is the default value if x not found

refs: https://stackoverflow.com/questions/60208/replacements-for-switch-statement-in-python