A limit to writing to a file from a loop?
DL Neil
PythonList at DancesWithMice.info
Tue Feb 12 14:12:43 EST 2019
Steve,
On 13/02/19 7:56 AM, Steve wrote:
> My program reads from a text file (A), modifies the data, and writes to another file (B).
> This works until I reach about 300 writes and no more lines are written to file (B).
> I had to create a Counter and increment it to 250 when it gets reset.
> Upon reset, I close the file (B) being written and reopen it for append.
> Then it accepts the entire list of lines of data.
> Bizarre?
>
>
> CycleCounter += 1
> if CycleCounter > 250:
> CycleCounter = 1
> DateReadings.close()
> DateReadings=open("Date-ReadingsAndDoses.txt", "a")
> DateReadings.write("{0:15} {1:>8} {2:>8} {3:>8} {4:<2} {5:>8} {6:>8} {7:>10}".format
> (ThisTimeDate, ThisReading, ThisDose1, ThisSensor, ThisTrend,
> ThisTS, ThisPercent, SensorNumberDay2) + "\n")
Perhaps part of the transfer to email, but won't this code only output
once per 250 records, cf 250 records per cycle?
Some suggestions:-
Test one: Prove that there is valid input
- is the code successfully reading more than '250' records?
Test two: Check the actual data
- is there anything strange about the '250th' record (the one that first
exhibits the problem)?
Test three: Prove that it is not some Python<->file system issue
- what happens if the first input record is written (to a 'junk file')
250+ times?
Test four: (possibly unnecessary after the above) Disprove a size issue
- what happens if you output a simple/hello world string (of the same
number of bytes) instead of the incoming data, 250+ times?
Report back. If there are still problems, please show the original code
and exception report...
--
Regards =dn
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