histogram

Histogram is a small python script that generates a histogram of values read from stdin.

Sample outputs:

We can get a traditional histogram of some numbers:

$ (seq 10; seq 20; seq 30) | histogram
below cmd output started 2020 Wed Oct 14 10:12:25 AM PDT
18 1 <= x < 7    ************************************************************
16 7 <= x < 13   *****************************************************
12 13 <= x < 19  ****************************************
 8 19 <= x < 25  ***************************
 6 25 <= x <= 30 ********************

We can get a "string histogram" of permissions under /usr/local/cpython-3.7, recursively; this is not traditionally called a "histogram":

$ find /usr/local/cpython-3.7 -print0 | xargs -0 ls -ld | awk ' { print $1 }' | histogram
    2 -r-xr-xr-x 
17243 -rw-r--r-- ************************************************************
  650 -rwxr-xr-x **
 1341 drwxr-xr-x *****
   84 lrwxrwxrwx

Note that if you do not care about the stars or percentages, then you can do a "string histogram" (but not a numeric histogram) with sort | uniq -c; these tools are included in almost any *ix:

$ find /usr/local/cpython-3.7 -print0 | xargs -0 ls -ld | awk ' { print $1 }' | sort | uniq -c
below cmd output started 2019 Sun Feb 17 06:41:35 PM PST
      2 -r-xr-xr-x
  15482 -rw-r--r--
    355 -rwxr-xr-x
   1018 drwxr-xr-x
     84 lrwxrwxrwx

The usage message looks like:

Usage: ./histogram
	--bin-function specifies the function used to compute the width of the bins
	   EG: --bin-function "square root" specifies the numeric bin widths will be computed using the square root rule
	--display-width specifies the width of the largest count (for the stars; default: 60.0)
	--elide elides the stars (overrides --display-width)
	--suppress-zeros says to eliminate zero counts from the report.  Only relevant for numeric histograms
	--force-string tells this program to treat numbers as strings
	--help outputs this usage message
	--percent gives percentages
	--tabbed says to separate fields with tabs instead of spaces, suitable for piping to expand(1)
	--input-file fn says to read values from file fn instead of stdin (mostly for debugging this program

If all values read from stdin can be converted to decimal, bin widths will be the decile of the range - or
other bin width function, as specified.  Otherwise, each distinct str read from stdin will be treated as a bin.

IOW, if you feed ./histogram lots of numbers, and get one bin for each distinct number, then you've probably
fed it one or more values that cannot be converted to decimal.Decimal().

Decile choice is used for numeric binning by default.

Valid choices for bin width functions are:
	square root
	sturges formula
	rice rule
	quartile
	decile
	twentyfifth-ile
	percentile

Please note that the numeric binning algorithm is no longer O(n) in the number of bins.  It is now a more
reasonable O(logn).

You can check it out / download it here.

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Timestamp: 2024-12-27 08:14:39 PST

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