Question

我正在尝试查找每个正值序列的起始位置的索引。我只在代码中得到了正值的位置。我的代码如下：

this.state = {
  barChart: { 
   options: {
      plotOptions: {
        xaxis: {
          categories: []
       }}}
        series: [{name: [], data: []}}

我希望[-1.1、2.0、3.0、4.0、5.0，-2.0，-3.0，-4.0、5.5、6.6、7.7、8.8、9.9]的输出为[1、8]

Answer 1

当前您选择的是数字为正的所有索引，相反，您只想在数字从负转换为正时才收集索引。

此外，您还可以处理所有负数，也可以处理从正数开始的数字

def get_pos_indexes(lst):

    index = []

    #Iterate over the list using indexes
    for i in range(len(lst)-1):

        #If first element was positive, add 0 as index
        if i == 0:
            if lst[i] > 0:
                index.append(0)
        #If successive values are negative and positive, i.e indexes switch over, collect the positive index
        if lst[i] < 0 and lst[i+1] > 0:
            index.append(i+1)

    #If index list was empty, all negative characters were encountered, hence add -1 to index
    if len(index) == 0:
        index = [-1]

    return index

print(get_pos_indexes([-1.1, 2.0, 3.0, 4.0, 5.0, -2.0, -3.0, -4.0, 5.5, 6.6, 7.7, 8.8, 9.9]))
print(get_pos_indexes([2.0, 3.0, 4.0, 5.0, -2.0, -3.0, -4.0, 5.5, 6.6, 7.7, 8.8, 9.9]))
print(get_pos_indexes([2.0,1.0,4.0,5.0]))
print(get_pos_indexes([-2.0,-1.0,-4.0,-5.0]))

输出将为

[1, 8]
[0, 7]
[0]
[-1]

Answer 2

我认为如果您使用列表理解

会更好

index = [i for i, x in enumerate(lst) if x > 0]

在列表中找到第一个正元素的索引-python

2 个答案: