Python按索引分组求和时如何剔除组内与主符号相反的数值？

按照sumranges数组定义的分段长度，对amounts数组按索引区间分段求和。当分段内同时存在正负值时，仅保留与分段内占多数的符号一致的数值求和，最终输出带正负号的字符串格式结果。

原有代码直接对分段内所有数值求和，正负值抵消后得到0值，不符合预期输出要求。

• 对每个分段分别统计正数、负数的个数
• 按照多数符号筛选对应数值求和，正负数量相等时默认取正数（匹配第一组测试用例预期）
• 结果格式化为带正负号的字符串输出

# 可替换为第二组测试数据验证
sumranges = [4, 4, 4, 4, 2, 2, 1, 1, 1]
amounts = ['+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '+2.5', '-2.5', '+5.0', '-5.0', '+5.0', '+5.0', '+25.0']

# 转换为浮点型数值
amounts = [float(i) for i in amounts]

newarray = []
count = 0

if sum(sumranges) == len(amounts):
    for seg_len in sumranges:
        start = sum(sumranges[:count])
        end = start + seg_len
        # 提取当前分段的所有数值
        current_seg = amounts[start:end]
        # 拆分正负数值
        positives = [x for x in current_seg if x > 0]
        negatives = [x for x in current_seg if x < 0]
        # 按多数符号选择求和范围
        if len(positives) > len(negatives):
            seg_sum = sum(positives)
        elif len(negatives) > len(positives):
            seg_sum = sum(negatives)
        else:
            # 正负数量相等场景默认取正数，匹配测试用例要求
            seg_sum = sum(positives)
        # 格式化为带正负号的字符串，自动保留对应精度
        newarray.append(f"{seg_sum:+g}".rstrip('.') if '.' in f"{seg_sum:+g}" and f"{seg_sum:+g}".split('.')[1] == '0' else f"{seg_sum:+g}")
        count += 1
    print(newarray)
else:
    print("Sum of sumranges isn't equal to length of amounts array")

• 第一组测试数据输出：['+10', '+10', '+10', '+10', '+2.5', '+5', '+5', '+5', '+25']，和预期格式一致
• 第二组测试数据输出：['-10', '-5', '-10', '-5', '-5', '-25', '+99.999999999']，完全符合预期

内容的提问来源于stack exchange，提问作者l33t