Question

刚刚接受了一些帮助，因为我是python的新手。我有一个文件，它是一个输出文件，由外部进程不断写入数据。我打算在此文件中查看＆＃39; x＆＃39;一段时间并将输出打印到屏幕和/或将其存储在列表/字典/元组中（不确定python术语中的适当内容）。

这就是我现阶段所拥有的：

timeout = time.time() + args.duration
with open('/dev/input/accel', 'rb') as o:
    while time.time() < timeout:
        data = o.read(16)
        sec, microsec, valtype, axis, axisval = struct.unpack(
            'LLHHi', data)
        tampertime = float(str(sec) + '.' + str(microsec))

        if valtype == 3:
            print(tampertime, axis, axisval)

输出就是这个（来自结构）：

secs.microsecs, axis, axis value
---------------------------
1478574443.4219799, 0, 4080
1478574443.4219799, 1, 1168
1478574443.4219799, 2, -15408
1478574443.542166, 0, 4016
1478574443.542166, 1, 1104
1478574443.6621571, 0, 4022
1478574443.6621571, 1, 1120
1478574443.6621571, 2, -15404
1478574443.7821031, 0, 4016
1478574443.7821031, 1, 1216
1478574443.7821031, 2, -15430
1478574443.9019749, 0, 4022
1478574443.9019749, 1, 1152
1478574444.2220099, 1, 1148
1478574444.2220099, 2, -15344

注意：我刚刚添加了逗号以便于阅读。

它也打印出其他值，但我只想要valtype == 3（这是上面输出中没有显示的列）的数字。

要快速解释这三列，第一列是时间（epoch / unix），第二列是＆＃39;键＆＃39;第三个是与密钥相关的值。您会注意到，如果键值没有变化，它只是从输出中省略它（我无法修复它，它只是输出文件处理值的方式）。

所以使用上面的输出，我正在寻找这种输出格式。

secs.microsecs, 0, 1, 2
----------------------------------------
1478574443.4219799, 4080, 1168, -15408*
1478574443.542166, 4016, 1104, -15408*
1478574443.6621571, 4022, 1120, -15404
1478574443.7821031, 4016, 1216, -15430*
1478574443.9019749, 4022*, 1152, -15430*
1478574444.2220099, 4022*, 1148, -15344

您会注意到我将旁边的星号放在旁边的值实际上与之前的值相对应（上图）。即，实际上没有为该时间戳提供任何值，因此它应该只使用存储的先前值。

我做了一些搜索并考虑过制作一个结构，但我没有运气。

非常感谢任何帮助。

Answer 1

您可以使用defaultdict：

from collections import defaultdict
d1=defaultdict(dict)
timeout = time.time() + args.duration
with open('/dev/input/accel', 'rb') as o:
    while time.time() < timeout:
        data = o.read(16)
        sec, microsec, valtype, axis, axisval = struct.unpack(
            'LLHHi', data)
        tampertime = float(str(sec) + '.' + str(microsec))
        if valtype == 3:
            d1[tampertime][axis] = axisval # dict with all values

tmp = {0: 0, 1: 0, 2:0}
for k in sorted(d1.keys()): #iterate through dict and customize output format
    for j in range(3):
        if d1[k].get(j) is None:
            d1[k][j] = tmp[j]
    tmp = d1[k]
    print(k, d1[k])

输出：

1478574443.42198 {0: 4080, 1: 1168, 2: -15408}
1478574443.542166 {0: 4016, 1: 1104, 2: -15408}
1478574443.662157 {0: 4022, 1: 1120, 2: -15404}
1478574443.782103 {0: 4016, 1: 1216, 2: -15430}
1478574443.901975 {0: 4022, 1: 1152, 2: -15430}
1478574444.22201 {0: 4022, 1: 1148, 2: -15344}

Answer 2

回答我自己的问题。因为我希望在每次执行后打印出值（一旦检索到x，y和z值），我就使用了这个解决方案。我注意到在我的二进制文件中有一个刷新值，我可以轮询并检查以触发打印。

这基本上是我的完整代码：

class Sample:

    def __init__(self):
        self.x = None
        self.y = None
        self.z = None
        self.ts_sec = None
        self.ts_usec = None

    def print_val(self):
        print("{0}.{1},{2},{3},{4}".format(
            self.ts_sec, self.ts_usec, self.x, self.y, self.z))


def DisplaySamples(samples):
    for s in samples:
    s.print_val()


def UpdateSample(data, sample):
    flush = False
    sec, usec, valtype, axis, axisval = struct.unpack('LLHHi', data)

    sample.ts_sec = sec
    sample.ts_usec = usec
    if valtype == 3:
        if axis == 0:
            sample.x = axisval
        if axis == 1:
            sample.y = axisval
        if axis == 2:
            sample.z = axisval
    if valtype == 0:
        flush = True

    return sample, flush


def main():
    with open('/dev/input/accel', 'rb') as o:
        sample = Sample()
        while time.time() < timeout:
            data = o.read(16)

            sample, flush = UpdateSample(data, sample)

            if flush:
                DisplaySamples([sample])
    o.close()

输出示例，csv格式化。

1478733511.251977,2896,-367,None
1478733511.372184,2768,-343,-15648
1478733511.492175,2752,-337,-15776
1478733511.612123,2888,-408,-15648
1478733511.732160,2888,-408,-15728
1478733511.852204,2868,-320,-15608
1478733511.972208,2838,-384,-15624
1478733512.92151,2819,-388,-15624
1478733512.212153,2819,-370,-15856
1478733512.332126,2888,-370,-15664
1478733512.452203,2860,-370,-15776
1478733512.572205,2882,-345,-15608
1478733512.692160,2768,-350,-15760
1478733512.812114,2880,-350,-15760
1478733512.932126,2768,-416,-15696
1478733513.52211,2840,-444,-15690

将二进制输出中的值存储到list / dictionary / tuple（Python）

2 个答案: