I would like to read a CSV file from the standard input and process each row as it comes. My CSV outputting code writes rows one by one, but my reader waits the stream to be terminated before iterating the rows. Is this a limitation of csv
module? Am I doing something wrong?
My reader code:
import csv
import sys
import time
reader = csv.reader(sys.stdin)
for row in reader:
print "Read: (%s) %r" % (time.time(), row)
My writer code:
import csv
import sys
import time
writer = csv.writer(sys.stdout)
for i in range(8):
writer.writerow(["R%d" % i, "$" * (i+1)])
sys.stdout.flush()
time.sleep(0.5)
Output of python test_writer.py | python test_reader.py
:
Read: (1309597426.3) ['R0', '$']
Read: (1309597426.3) ['R1', '$$']
Read: (1309597426.3) ['R2', '$$$']
Read: (1309597426.3) ['R3', '$$$$']
Read: (1309597426.3) ['R4', '$$$$$']
Read: (1309597426.3) ['R5', '$$$$$$']
Read: (1309597426.3) ['R6', '$$$$$$$']
Read: (1309597426.3) ['R7', '$$$$$$$$']
As you can see all print statements are executed at the same time, but I expect there to be a 500ms gap.
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