1DBCOLHISTO(1) User Contributed Perl Documentation DBCOLHISTO(1)
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6 dbcolhisto - compute a histogram over a column of Fsdb data
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9 dbcolhisto [-ag] [-W BucketWidth] [-S BucketStart] [-E BucketEnd] [-N
10 NumberOfBuckets] column
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13 This program computes a histogram over a column of data. Records
14 containing non-numeric data are considered null do not contribute to
15 the stats (optionally they are treated as zeros).
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17 Defaults to 10 buckets over the exact range of data. Up to three
18 parameters (number of buckets, start, end, and width) can be specified,
19 the rest default accordingly.
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21 Buckets range from a value (given the the low column) to just below the
22 next low value and buckets are equal width. If necessary, extra "<min"
23 and ">max" buckets are created. By default, the last bucket includes
24 max (and is thus infinitesimally larger than the other buckets). This
25 irregularity can be removed with the "-I" option.
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27 This program requires O(number of buckets) memory and O(size of data)
28 temporary disk space.
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31 -W or --width N
32 Gives with width of each bucket, in data units. Default is
33 whatever gives 10 buckets over the whole range of data.
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35 -S or --start N
36 Buckets start at value N, in data units. Default is the minimum
37 data value.
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39 -E or --end N
40 Buckets end at value N, in data units. Default is the maximum data
41 value.
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43 -N or --number N
44 Create N buckets. The default is 10 buckets.
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46 -g or --graphical
47 Generate a graphical histogram (with asterisks). Default is
48 numeric.
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50 -I or --last-inclusive
51 Make the last bucket non-inclusive of the last value.
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53 -a Compute stats over all records (treat non-numeric records as zero
54 rather than just ignoring them). Default is non-numeric records
55 are ignored.
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57 -e EmptyValue or --empty
58 Specify the value any null bins get. (Default: -.)
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60 This module also supports the standard fsdb options:
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62 -d Enable debugging output.
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64 -i or --input InputSource
65 Read from InputSource, typically a file name, or "-" for standard
66 input, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue
67 objects.
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69 -o or --output OutputDestination
70 Write to OutputDestination, typically a file name, or "-" for
71 standard output, or (if in Perl) a IO::Handle, Fsdb::IO or
72 Fsdb::BoundedQueue objects.
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74 --autorun or --noautorun
75 By default, programs process automatically, but Fsdb::Filter
76 objects in Perl do not run until you invoke the run() method. The
77 "--(no)autorun" option controls that behavior within Perl.
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79 --help
80 Show help.
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82 --man
83 Show full manual.
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86 Input:
87 #fsdb name id test1
88 a 1 80
89 b 2 70
90 c 3 65
91 d 4 90
92 e 5 70
93 f 6 90
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95 Command:
96 cat DATA/grades.fsdb | dbcolhisto -S 0 -E 100 -N 10 test1
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98 Output:
99 #fsdb low histogram:q
100 0 0
101 10 0
102 20 0
103 30 0
104 40 0
105 50 0
106 60 1
107 70 2
108 80 1
109 90 2
110 # | dbcolhisto -S 0 -E 100 -N 10 test1
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113 Fsdb, dbcolpercentile, dbcolstats
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116 This program could run in constant memory with no external storage when
117 the buckets are pre-specified. That optimization is not implemented.
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120 Copyright (C) 1991-2022 by John Heidemann <johnh@isi.edu>
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122 This program is distributed under terms of the GNU general public
123 license, version 2. See the file COPYING with the distribution for
124 details.
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128perl v5.36.0 2022-11-22 DBCOLHISTO(1)