python - 循环元组并获取从高到低的转换列表的更有效方法

Question

我有一个输入整数值的元组，其值为high。我想循环遍历并取出元组中 >= high 的值的第一个实例对，然后取出 <high 的第一个值。一个例子可能会有所帮助:

仅保留每个重复高点或低点的第一个高点或第一个低点

例如，如果 max == 100，则输入为 (102, 109, 120, 80, 40, 30, 200, 90)

输出应为 [[102, 80], [200, 90]]

items = (102, 109, 120, 80, 40, 30, 200, 90)
high = 100
started = False  # Used to ensure we start with high values first
currently_on_highs = True
first_val_high = True
first_val_low = True
transitions = []
inner_transition = []

for item in items:
    if item >= high:
        started = True
        currently_on_highs = True
        if first_val_high:
            first_val_high = False
            first_val_low = True
            inner_transition.append(item)
    else:
        if started:
            currently_on_highs = False
            if first_val_low:
                first_val_high = True
                first_val_low = False
                inner_transition.append(item)
                transitions.append(inner_transition)
                inner_transition = []

print(transitions)

<小时/>

根据 @michael-butscher 的建议，这是一个更好的结果

items = (102, 109, 120, 80, 40, 30, 200, 90)
high = 100
in_high = False
transitions = []
inner_transition = []

for item in items:
    if item >= high and not in_high:
        in_high = True
        inner_transition.append(item)
    elif item < high and in_high:
        in_high = False
        inner_transition.append(item)
        transitions.append(inner_transition)
        inner_transition = []

print(transitions)

Answer 1

您可以使用 zip 轻松完成此操作，方法是将元素偏移一个条目，以将每个元素与其前一个条目进行比较:

items  = (102, 109, 120, 80, 40, 30, 200, 90)
high   = 100
bounds = [ num for prev,num in zip((high-1,)+items,items) if (num<high)^(prev<high) ] 
result = list(zip(bounds[::2],bounds[1::2]))
print(result) # [(102, 80), (200, 90)]