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POPython (beginner): CSV column writing, unexpected output for time-autocorrelation function
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copied!<p>Trying to write a fourth column to a set of data which looks like this </p> <pre><code> 8000.5 16745 0.1257 8001.0 16745 0.1242 8001.5 16745 0.1565 8002.0 16745 0.1595 </code></pre> <p>Which has the number of times the second number (i.e. 16745) has been counted in that particular file (it does change, the list has a couple thousand entries). i.e. if this were the whole file</p> <pre><code> 8000.5 16745 0.1257 4 8001.0 16745 0.1242 4 8001.5 16745 0.1565 4 8002.0 16745 0.1595 4 </code></pre> <p>The problem with my code seems to be in the writing stage, the dictionary works, and csv.reader is reading the file fine if I print it but when it comes to appending the only dictionary key it picks up (field[1]) seems to be one where 16745 is -1 and the count of this is printed in the fourth column for all rows. I can't understand why it is cross referencing with the dictionary only for this value and not on a per row basis.</p> <p>i.e. I get </p> <pre><code> 8000.5 16745 0.1257 [count of -1 in column 2] 8001.0 16745 0.1242 [count of -1 in column 2] 8001.5 16745 0.1565 [count of -1 in column 2] 8002.0 16745 0.1595 [count of -1 in column 2] </code></pre> <p>Any help would be greatly appreciated! </p> <pre><code>import numpy import string import csv import sys import os time = [] water = [] itemcount ={} global filename filename = sys.argv[1] f1 = open(sys.argv[1], 'rt') for line in f1: fields = line.split() time.append(fields[0]) water.append(fields[1]) f1.close() for x in water: a = water.count(x) itemcount[x] = a writerfp = open('watout.csv', 'w') writer = csv.writer(writerfp) for row in csv.reader(open(filename, 'r')): fields = line.split() row.append(itemcount[fields[1]]) writer.writerow(row) writerfp.close() </code></pre>

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