能否将Python中这段条件判断代码改写为一行代码？

我有一段Python程序，完整代码如下：

from collections import Counter

def balance(left, right, result = 0):
    wages = {'!': 2, '?': 3}
    for key in Counter(left).keys():
        result += Counter(left).get(key) * wages.get(key)
    for key_ in Counter(right).keys():
        result -= Counter(right).get(key_) * wages.get(key_)
    if result == 0:
        return 'Balance'
    return 'Left' if result > 0 else 'Right'

请问能不能把这段条件判断代码改成一行？

if result == 0:
    return 'Balance'
return 'Left' if result > 0 else 'Right'

完全可以，用嵌套三元表达式就能把这段逻辑浓缩成一行：

return 'Balance' if result == 0 else 'Left' if result > 0 else 'Right'

如果觉得嵌套的三元表达式可读性差点，可以加个括号明确优先级，看起来更清楚：

return 'Balance' if result == 0 else ('Left' if result > 0 else 'Right')

另外顺带提一句，你原代码里计算左右重量的循环部分也能简化，用生成器表达式配合sum()函数，代码会更简洁高效：

from collections import Counter

def balance(left, right):
    wages = {'!': 2, '?': 3}
    left_weight = sum(count * wages[char] for char, count in Counter(left).items())
    right_weight = sum(count * wages[char] for char, count in Counter(right).items())
    result = left_weight - right_weight
    return 'Balance' if result == 0 else 'Left' if result > 0 else 'Right'

内容的提问来源于stack exchange，提问作者Ashtart