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Switch in D Programming Language
Switch Statements in Python
Switch statements express conditionals across many branches.
Here’s a basic switch, implemented using a dictionary in Python:
def simple_switch(i):
print(f"Write {i} as", end=" ")
switcher = {
1: "one",
2: "two",
3: "three",
}
print(switcher.get(i, "Invalid number"))
simple_switch(2)You can use if-elif-else to separate multiple conditions in the same case statement. We use the optional else case in this example as well:
from datetime import datetime
def weekday_switch():
today = datetime.today().strftime("%A")
if today in ["Saturday", "Sunday"]:
print("It's the weekend")
else:
print("It's a weekday")
weekday_switch()Using a switch without an expression is an alternate way to express if/else logic. Here we also show how the case expressions can be non-constants:
def time_switch():
now = datetime.now()
hour = now.hour
if hour < 12:
print("It's before noon")
else:
print("It's after noon")
time_switch()A type switch compares types instead of values. You can use this to discover the type of a variable. In this example, the variable t will have the type corresponding to its clause:
def what_am_i(i):
if isinstance(i, bool):
print("I'm a bool")
elif isinstance(i, int):
print("I'm an int")
else:
print(f"Don't know type {type(i).__name__}")
what_am_i(True)
what_am_i(1)
what_am_i("hey")$ python switch.py
Write 2 as two
It's a weekday
It's after noon
I'm a bool
I'm an int
Don't know type strNext example: Arrays.