Berkeley CSUA MOTD:Entry 54650
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2017/11/19 [General] UID:1000 Activity:popular
11/19   

2013/4/9-5/18 [Computer/SW/Languages/C_Cplusplus, Computer/SW/Apps, Computer/SW/Languages/Perl] UID:54650 Activity:nil
4/04    Is there a good way to diff 2 files that consist of columns of
        floating point numbers, such that it only tells me if there's a
        difference if the numbers on a given line differ by at least a given
        ratio?  Say, 1%?
        \_ Use Excel.
           1. Open foo.txt in Excel.  It should convert all numbers to cells in
              column A.
           2. Open bar.txt in Excel.  Ditto.
           3. Create a new file in Excel.
           4. In cell A1 of the new file, enter this:
              =IF(foo.txt!A1=0, IF(bar.txt!A1=0, "same", "different"), IF(ABS((b\
ar.txt!A1-foo.txt!A1)/foo.txt!A1)<1%, "same", "different"))
           5. Select cell A1.  Hit Ctrl-C to copy.
           6. Select the same number of cells as the number of cells that exist
              in foo.txt or bar.txt.  Hit Ctrl-V to paste.
           7. Hit Ctrl-F.  In "Find what:", enter "different".  In "Look in:",
              choose "Values".  Click "Find All".
           Another way is to write a C program to read the two files using
           fscanf("%f") an do the arithmatic.
        \_ does this help?
#!/usr/bin/python
import sys

threshold = float(sys.argv[3] if len(sys.argv) > 3 else 0.0000001)
list1 = [float(v) for v in open(sys.argv[1]).readlines()]
list2 = [float(v) for v in open(sys.argv[2]).readlines()]

line = 1
for v1, v2 in zip(list1, list2):
    if abs((v1 - v2) / v1) >= threshold:
        print "Line %d different (%f != %f)" % (line, v1, v2)
    line += 1
        \_ Something like this might work ($t is your threshold):
           $ perl -e '$t = 0.1 ; while (<>) { chomp($_); ($i,$j) =
             split(/ \t/, $_); if ($i > ((1+$t)*$j) || $i < ((1-$t)*j)) {
             print "$_\n"; }}' < file
2017/11/19 [General] UID:1000 Activity:popular
11/19   

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