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pythonpython-3.xfilefilesplitting

How to split file with certain conditions for each end line of each file


I have a .txt file like this:

2019-03-29 12:03:07 line1 
                    line2
                    line3
                    ....
2019-03-30 07:05:09 line1
                    line2
                    ....
2019-03-31 10:03:20 line1
                    line2
                    ....

I split the file into several files, like this:

inputData = 'dirname\..'
numThrd  = 3
def chunkFiles():
    nline = sum(1 for line in open(inputData,'r', encoding='utf-8', errors='ignore'))
    chunk_size = math.floor(nline/int(numThrd))
    n_thread = int(numThrd)
    j = 0
    with open(inputData,'r', encoding='utf-8', errors='ignore') as fileout:
        for i, line in enumerate(fileout):
            if (i + 1 == j * chunk_size and j != n_thread) or i == nline:
                out.close()
            if i + 1 == 1 or (j != n_thread and i + 1 == j * chunk_size):
                chunkFile = 'rawData' + str(j+1) + '.txt'
                if os.path.isfile(chunkFile ):
                    break
                out = open(chunkFile , 'w+', encoding='utf-8', errors='ignore')
                j = j + 1
                fLine = line[:-1]
                if not matchLine:
            if out.closed != True:
                out.write(line)
            if i % 1000 == 0 and i != 0:
                print ('Processing line %i ...' % (i))

However, I want the split file to meet the condition that the last line in the chunk file must be right before the line that has the date.

recent output that I got:

rawData1.txt
2019-03-29 12:03:07 line1
                    line2
                    ....
-------------------------
rawData2.txt
                    line50
                    line51
2019-03-30 07:05:09 line1
                    line2
                    .....

Desired output:

rawData1.txt
2019-03-29 12:03:07 line1 
                    line2
                    line3
                    ....
-------------------------
rawData2.txt
2019-03-30 07:05:09 line1
                    line2
                    ....

what should I add to the script above to meet that conditions?

Thank you very much


Solution

  • You can produce the desired output by using a list to hold the lines you want to write (see below).

    def write_chunk(filename, chunk):
        with open(filename, "w") as out:
            for i in chunk:
                out.write(i)
    
    chunk = []
    n_chunk = 1
    
    with open("data.txt") as f:
        for line in f:
            if not line[0].isspace() and chunk:
                write_chunk("{}.txt".format(n_chunk), chunk)
                chunk = []
                n_chunk += 1
            chunk.append(line)
    # write final chunk
    write_chunk("{}.txt".format(n_chunk), chunk)