Python中高级语法糖的使用示例详解

numbers = [1, 2, 3, 4, 5]
squared_numbers = [x**2 for x in numbers]
print(squared_numbers)
# 输出: [1, 4, 9, 16, 25]

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
even_numbers = [x for x in numbers if x % 2 == 0]
print(even_numbers)
# 输出: [2, 4, 6, 8, 10]

words = ['hello', 'world', 'python', 'programming']
word_lengths = {word: len(word) for word in words}
print(word_lengths)
# 输出: {'hello': 5, 'world': 5, 'python': 6, 'programming': 11}

numbers = [1, 2, 2, 3, 3, 4, 5, 5]
unique_numbers = {x for x in numbers}
print(unique_numbers)
# 输出: {1, 2, 3, 4, 5}

numbers = [1, 2, 3, 4, 5]
squared_numbers = (x**2 for x in numbers)
print(squared_numbers)
# 输出: <generator object <genexpr> at 0x7f3bc5360510>
for n in squared_numbers:
    print(n)
# 输出: 1 4 9 16 25

with open('example.txt', 'r') as file:
    data = file.read()
# 在离开with块时，文件会自动关闭

class MyRange:
    def __init__(self, start, end):
        self.current = start
        self.end = end
 
    def __iter__(self):
        return self
 
    def __next__(self):
        if self.current >= self.end:
            raise StopIteration
        else:
            self.current += 1
            return self.current - 1
 
my_range = MyRange(1, 5)
for num in my_range:
    print(num)
# 输出: 1 2 3 4

a, b = 10, 20
a, b = b, a  # 交换a和b的值
print(a, b)
# 输出: 20 10

for i in range(5):
    print(i)
else:
    print("循环正常结束")
# 输出:
# 0
# 1
# 2
# 3
# 4
# 循环正常结束
 
for i in range(5):
    if i == 3:
        break
    print(i)
else:
    print("循环正常结束")
# 输出:
# 0
# 1
# 2

fruits = ['apple', 'banana', 'cherry']
for index, fruit in enumerate(fruits):
    print(f"Index: {index}, Fruit: {fruit}")
# 输出:
# Index: 0, Fruit: apple
# Index: 1, Fruit: banana
# Index: 2, Fruit: cherry

names = ['Alice', 'Bob', 'Charlie']
scores = [85, 92, 78]
for name, score in zip(names, scores):
    print(f"Name: {name}, Score: {score}")
# 输出:
# Name: Alice, Score: 85
# Name: Bob, Score: 92
# Name: Charlie, Score: 78