问题描述
所以，我有一个可以自行更新的 .csv 文件.我想用它做一些事情，但不知道如何处理它，希望你能帮助我.csv 中的数据如下所示:没有标题.我也可以在没有分隔符的情况下将日期和时间加入到同一列中.
So, I have a .csv file which updates itself. I would like to do some things with it and am not sure how to approach it, hope you can help me.The data in the csv looks like this:There is no headers. I can join the date and time to be in same column without a delimiter too.
07/12/2017,23:50,113.179,113.182,113.168,113.180,113.187,113.189,113.176,113.186,144
07/12/2017,23:51,113.180,113.190,113.180,113.187,113.186,113.196,113.186,113.193,175
07/12/2017,23:52,113.187,113.188,113.174,113.186,113.193,113.194,113.181,113.192,340
07/12/2017,23:53,113.186,113.192,113.175,113.181,113.192,113.199,113.182,113.188,282
07/12/2017,23:54,113.181,113.183,113.170,113.171,113.188,113.188,113.176,113.179,74
07/12/2017,23:55,113.171,113.181,113.170,113.179,113.179,113.188,113.176,113.186,329
07/12/2017,23:56,113.179,113.189,113.174,113.181,113.186,113.195,113.181,113.187,148
07/12/2017,23:57,113.181,113.181,113.169,113.169,113.187,113.187,113.175,113.175,55
07/12/2017,23:58,113.169,113.183,113.169,113.182,113.175,113.188,113.175,113.187,246
07/12/2017,23:59,113.182,113.210,113.175,113.203,113.187,113.215,113.181,113.209,378
08/12/2017,00:00,113.203,113.213,113.180,113.183,113.209,113.220,113.187,113.190,651
08/12/2017,00:01,113.183,113.190,113.164,113.167,113.190,113.196,113.171,113.174,333
08/12/2017,00:02,113.167,113.182,113.156,113.156,113.174,113.188,113.162,113.163,265
08/12/2017,00:03,113.156,113.165,113.151,113.163,113.163,113.172,113.158,113.170,222
08/12/2017,00:04,113.163,113.163,113.154,113.159,113.170,113.170,113.159,113.166,148
08/12/2017,00:05,113.159,113.163,113.153,113.154,113.166,113.168,113.159,113.162,162
对于初学者来说，我有兴趣在本练习中只使用前两列(如果日期和时间分开，则使用前 3 列).例如:
For starters I would be interested in using just the first two (or 3 if date and time are separate) columns for this exercise. So for example:
07/12/2017,21:54,113.098
07/12/2017,21:55,113.096
07/12/2017,21:56,113.087
07/12/2017,21:57,113.075
07/12/2017,21:58,113.087
07/12/2017,21:59,113.079
每隔一秒左右就会添加新行，日期时间更新.我可以做类似的事情
New rows are being added with more recent date time every second or so.I can do something like
df = pd.read_csv("C:\\Users\\xxx\\Desktop\\csvexport\\thefile.csv")
print(df[-1:])
查看数据帧的最后一行(尾部)
To see the last row (tail) from the dataframe
现在，我不知道如何执行以下操作，感谢您的帮助:
Now, I can't see how to do the following and appreciate your help:
更新数据框，以便我可以使用最新版本来计算何时出现新行(不使用睡眠定时器?)
Update the dataframe so that I have the most recent version up to date available to make calculations on when new rows appear (without using sleep timer?)
能够在新数据到达时自动反映在图中的新更新数据绘制数据(x 轴上的日期时间，y 上的浮动)
Be able to plot the data with the newly updating data being reflected in the plot automatically as new data arrives (datetime on x axis, float on y)
我在生成 .csv 文件的程序的命令窗口中看到的输出是这样的，如果这很重要
The output I see in the command window from the program generating the .csv file is like this, if that matters
asset 08/12/2017 05:16:37 float:113.336 floattwo:113.328 digit:20
asset 08/12/2017 05:16:40 float:113.334 floattwo:113.328 digit:21
asset 08/12/2017 05:16:40 float:113.335 floattwo:113.323 digit:22
asset 08/12/2017 05:16:41 float:113.331 floattwo:113.328 digit:23
asset 08/12/2017 05:16:43 float:113.334 floattwo:113.327 digit:24
asset 08/12/2017 05:16:47 float:113.332 floattwo:113.328 digit:25
所以你可以看到更新间隔不是一秒，它们可能有间隔，有时也可能发生在同一秒内(05:16:40 两次)
So you can see the updates are not exactly one second apart, they can have gaps, and can sometimes occur within the same second too (05:16:40 twice)
因此，我想要发生的是实际上以相等的时间间隔(1 分钟或 5 分钟等)保持绘图，但根据属于该分钟的 .csv 中的浮点值不断更改最近的点.当下一分钟的一行到来时，情节才应该向右移动(但随着浮点数的变化而不断波动)......希望你明白.我想使用 pyqtgraph 作为绘图.
Therefore, what I would like to happen is keep the plot at equal time intervals actually (1 minute, or 5 minutes, etc) but keep changing the most recent point according to the float vlaue in the .csv belonging to that minute. When a row with the next minute arrives, only then should the plot move to the right (but constantly fluctuate in value as the float number is changing)... Hope you get the idea. I would like to use pyqtgraph for the plot.
我设法编写了这么多代码......但这不是最好的例子，对不起.当然，情节并不是这样的.只是说明我想看到的.所以绿色条应该不断改变值，直到下一个时间步被添加到 csv
I managed to code this much... but it is not the greatest example, excuse me. Of course the plot is not meant to look like this. Just illustrating what I would like to see. So the green bar should be changing value constantly until the next time step is added to the csv
import pyqtgraph as pg
from pyqtgraph import QtCore, QtGui
import pandas as pd
import datetime
x = pd.read_csv("C:\\Users\\xxx\\Desktop\\csvexport\\thefile.csv")
z = x[-1:]
def getlastrow():
for a in z.iterrows():
d = ((int(((a[1][0]).split("/")[0]))))
m = ((int(((a[1][0]).split("/")[1]))))
y = ((int(((a[1][0]).split("/")[2]))))
hh = ((int(((a[1][1]).split(":")[0]))))
mm = ((int(((a[1][1]).split(":")[1]))))
#ss = ((int(((a[1][1]).split(":")[2]))))
thedate = datetime.date(y, m, d)
thetime = datetime.time(hh, mm)
p = (a[1][2])
return ((thedate,thetime,p))
# print(str(getlastrow()[0]).replace("-",""))
# print(getlastrow()[1])
# print(getlastrow()[2])
class CandlestickItem(pg.GraphicsObject):
def __init__(self):
pg.GraphicsObject.__init__(self)
self.flagHasData = False
def set_data(self, data):
self.data = data
self.flagHasData = True
self.generatePicture()
self.informViewBoundsChanged()
def generatePicture(self):
self.picture = QtGui.QPicture()
p = QtGui.QPainter(self.picture)
p.setPen(pg.mkPen('w'))
w = (self.data[1][0] - self.data[0][0]) / 2.
for (t, open) in self.data:
p.drawLine(QtCore.QPointF(t, open), QtCore.QPointF(t, open))
p.setBrush(pg.mkBrush('r'))
if open > 122.8:
p.setBrush(pg.mkBrush('g'))
p.drawRect(QtCore.QRectF(t-w, open, w*2, open))
p.end()
def paint(self, p, *args):
if self.flagHasData:
p.drawPicture(0, 0, self.picture)
def boundingRect(self):
return QtCore.QRectF(self.picture.boundingRect())
app = QtGui.QApplication([])
data = [
[(int(str(getlastrow()[0]).replace("-",""))), (getlastrow()[2])],
[(int(str(getlastrow()[0]).replace("-","")))+1, (getlastrow()[2])+0.1],
[(int(str(getlastrow()[0]).replace("-","")))+2, (getlastrow()[2])+0.2],
]
item = CandlestickItem()
item.set_data(data)
plt = pg.plot()
plt.addItem(item)
plt.setWindowTitle('pyqtgraph example: customGraphicsItem')
def update():
global item, data
new_bar = (int(str(getlastrow()[0]).replace("-","")))+3, ((getlastrow()[2])+10)
data.append(new_bar)
item.set_data(data)
app.processEvents()
timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(100)
if __name__ == '__main__':
import sys
if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
QtGui.QApplication.instance().exec_()
推荐答案
希望下面的代码对第 (1) 点有所帮助.我意识到这是部分答案.我用Linux测试过.代码应该与操作系统无关，但我尚未对此进行测试.
Hopefully the code below will help with point(1). I realise this is a partial answer. I tested using Linux. The code should be OS agnostic, but I have not tested this.
代码使用看门狗库监控TEST_DIR中定义的目录.如果 TEST_FILE 中定义的文件发生更改，则会从名为 MyHandler 的事件处理类向主函数发送一条消息.我投入了一些丑陋的时间检查，因为每次更改文件时都会触发多个事件.因此，对于在 THRESHOLD 时间内发生的事件，只会触发单个分派.我将其设置为 0.01 秒.
The code monitors the directory defined in TEST_DIR using the watchdog library. If the file defined in TEST_FILE is changed, then a message is sent from the event handling class called MyHandler to the main function. I put in some ugly time checking as each time a file is altered, multiple events are triggered. So only a single dispatch will be triggered for events occurring within THRESHOLD time. I set this to 0.01 s.
向 dispatcher_receiver 函数添加代码以读取更新的文件.
Add code to the dispatcher_receiver function to read in the updated file.
import ntpath
# pip3 install pydispatcher --user
from pydispatch import dispatcher
import sys
import time
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler
MYHANDLER_SENDER = 'myhandler_sender'
MYHANDLER_SIGNAL = 'myhandler_signal'
TEST_FILE = 'test_data.csv'
TEST_DIR = '/home/bill/data/documents/infolab2/progs/jupyter_notebooks/pyqtgraph/test_data/'
THRESHOLD_TIME = 0.01
class MyHandler(FileSystemEventHandler):
''' handle events from the file system '''
def __init__(self):
self.start_time = time.time()
def on_modified(self, event):
now_time = time.time()
# filter out multiple modified events occuring for a single file operation
if (now_time - self.start_time) < THRESHOLD_TIME:
print('repeated event, not triggering')
return
changed_file = ntpath.basename(event.src_path)
if changed_file == TEST_FILE:
print('changed file: {}'.format(changed_file))
print('event type: {}'.format(event.event_type))
print('do something...')
# print(event)
message = '{} changed'.format(changed_file)
dispatcher.send(message=message, signal=MYHANDLER_SIGNAL, sender=MYHANDLER_SENDER)
self.start_time = now_time
def main():
dispatcher.connect(dispatcher_receive, signal=MYHANDLER_SIGNAL, sender=MYHANDLER_SENDER)
observer = Observer()
observer.schedule(event_handler, path=TEST_DIR, recursive=False)
observer.start()
try:
while True:
time.sleep(1)
except KeyboardInterrupt:
observer.stop()
observer.join()
def dispatcher_receive(message):
print('received dispatch: {}'.format(message))
# read in the altered file
if __name__ == "__main__":
event_handler = MyHandler()
main()
这篇关于读取和绘制实时实时自我更新 csv 文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！