How to read csv data alternately every 5 seconds in python-CodePudding

So I have a csv data and I want my program to read the data every 5 seconds. So between the first data and the second data there is a reading distance of 5 seconds. Can I use time.sleep() or is there another way to do it?

data_signal = np.loadtxt(pname   fname,
                      delimiter=';',
                      skiprows=1)
for i in range(len(data_signal)
      data = data_signal[i]
      time.sleep(5)

CodePudding user response：

Consider that time.sleep() is blocking further script execution. If you want things to run on timer and go on running your code consider to use a callback_timer class which you can adapt to your needs. Below code which demonstrates the principle of the callback timer:

from threading import Timer
class callback_timer():
    def __init__(self, data_signal=None, timespan=None):
        if not isinstance(data_signal, str) or not ( isinstance(timespan, int) or isinstance(timespan, float)): 
            raise Exception("callback_timer(): bad or not specified parameter")
        self.counter = len(data_signal)
        self.data_signal = data_signal
        self.timespan = timespan
        self.timer       = Timer(timespan, self.get_data, args=["noArgs"])
        self.timer.start()
        print( 'callback_timer() START' )
    def get_data(self, noArgs):
        curr_signal = self.data_signal[len(self.data_signal) - self.counter]
        print('callback_timer() countdown =', self.counter, "curr_signal=", curr_signal)
        ... # some code for processing curr_signal ...
        self.counter -= 1
        if self.counter < 1:
            print( 'callback_timer() STOP' )          
            return True
        self.timer       = Timer(self.timespan, self.get_data, args=["noArgs"])
        self.timer.start()

if __name__ == '__main__':
    data_signal = '0-1-ax' #  ... some data_signal'
    print ('Got to main(), timer message in 3 seconds.')
    cb = callback_timer(data_signal, 3) # doesn't block execution of next code line
    print ('main() after creation of test_timer() object')

giving following output:

Got to main(), timer message in 3 seconds.
callback_timer() START
main() after creation of test_timer() object
callback_timer() countdown = 6 curr_signal= 0
callback_timer() countdown = 5 curr_signal= -
callback_timer() countdown = 4 curr_signal= 1
callback_timer() countdown = 3 curr_signal= -
callback_timer() countdown = 2 curr_signal= a
callback_timer() countdown = 1 curr_signal= x
callback_timer() STOP

See also Python Timer Callback Method providing code stripped down to demonstration of the callback timer principle only.

CodePudding user response：

for z in range(1, len(YourFileOpen)):
     with open(f'{z}.csv') as csv_file:
         csv_reader = csv.reader(csv_file, delimiter=';')
         line_count = 0

     for row in csv_reader:
         value1 = row[0]
         value2 = row[2]

after this use print and (import time) after print insert your sleep:

print(f"{value1}\n{value2}\n")
time.sleep(5)