Python 中的控制流程

1x = 10
2
3if x > 5: # Check if the condition(x > 5) is True
4    # If the condition is True, execute this code block
5    print("x is greater than 5")

1x = 3
2
3if x > 5:
4    print("x is greater than 5")
5else:
6    print("x is less than or equal to 5")

1x = 5
2
3if x > 5:
4    print("x is greater than 5")
5elif x == 5:
6    print("x is equal to 5")
7else:
8    print("x is less than 5")

 1def switch_example(value):
 2    if value == 1:
 3        return "Value is one"
 4    elif value == 2:
 5        return "Value is two"
 6    elif value == 3:
 7        return "Value is three"
 8    else:
 9        return "Unknown value"
10
11print(switch_example(1))  # Output: Value is one
12print(switch_example(4))  # Output: Unknown value

 1def case_one():
 2    return "Value is one"
 3
 4def case_two():
 5    return "Value is two"
 6
 7def case_default():
 8    return "Unknown value"
 9
10def switch_example(value):
11    switch_dict = {
12        1: case_one,
13        2: case_two
14    }
15
16    # Use get() method to retrieve the corresponding function from the dictionary
17    # If the value is not found in the dictionary, use case_default as a fallback
18    return switch_dict.get(value, case_default)()
19
20print(switch_example(1))  # Output: Value is one
21print(switch_example(3))  # Output: Unknown value

 1def switch_example(value):
 2    match value:
 3        case 1:
 4            return "Value is one"
 5        case 2:
 6            return "Value is two"
 7        case 3:
 8            return "Value is three"
 9        case _:
10            return "Unknown value"
11
12print(switch_example(1))  # Output: Value is one
13print(switch_example(4))  # Output: Unknown value

1# Loop through each item in the iterable
2for variable in iterable:
3    # Execute this block of code for each item in the iterable
4    code_to_execute

1fruits = ["apple", "banana", "cherry"]
2for fruit in fruits:
3    print(fruit)

1for i in range(5):
2    print(i)

1person = {"name": "Alice", "age": 25}
2for key in person:
3    print(key, person[key])

1person = {"name": "Alice", "age": 25}
2for key, value in person.items():
3    print(key, value)

1matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
2for row in matrix:
3    for num in row:
4        print(num)

1for i in range(10):
2    if i == 5:
3        continue
4    if i == 8:
5        break
6    print(i)

1while condition:
2    # This block of code will be executed repeatedly as long as the condition is true
3    statement1
4    statement2
5    ...

1i = 1
2while i <= 5:
3    print(i)
4    i += 1

1i = 1
2while i <= 5:
3    if i == 3:
4        break  # Exit the loop when i becomes 3
5    print(i)
6    i += 1

1i = 0
2while i < 5:
3    i += 1
4    if i == 3:
5        # Skip the print statement and move to the next loop iteration when i is 3
6        continue
7    print(i)