[OSAB] Task 7: Add horizontal histograms

bashplotlib/horizontal_histogram.py

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+"""
+Plotting horizontal, terminal based histograms
+"""
+
+from __future__ import print_function
+
+import math
+from .utils.helpers import *
+from .utils.commandhelp import hist
+
+
+def plot_horiz_hist(f, width=20, bincount=None, binwidth=None, pch="o", title="", ylab=False, show_summary=False, regular=False):
+    """
+    Make a histogram
+
+    Arguments:
+        width -- the width of the histogram in # of lines
+        bincount -- number of bins in the histogram
+        binwidth -- width of bins in the histogram
+        pch -- shape of the bars in the plot
+        colour -- colour of the bars in the terminal
+        title -- title at the top of the plot
+        ylab -- boolen value for whether or not to display x-axis labels
+        show_summary -- boolean value for whether or not to display a summary
+        regular -- boolean value for whether or not to start y-labels at 0
+    """
+    if pch is None:
+        pch = "o"
+
+    if isinstance(f, str):
+        with open(f) as fh:
+            f = fh.readlines()
+
+    min_val, max_val = None, None
+    n, mean, sd = 0.0, 0.0, 0.0
+
+    for number in read_numbers(f):
+        n += 1
+        if min_val is None or number < min_val:
+            min_val = number
+        if max_val is None or number > max_val:
+            max_val = number
+        mean += number
+
+    mean /= n
+
+    for number in read_numbers(f):
+        sd += (mean - number)**2
+
+    sd /= (n - 1)
+    sd **= 0.5
+
+    bins = list(calc_bins(n, min_val, max_val, bincount, binwidth))
+    hist = dict((i, 0) for i in range(len(bins)))
+
+    for number in read_numbers(f):
+        for i, b in enumerate(bins):
+            if number <= b:
+                hist[i] += 1
+                break
+        if number == max_val and max_val > bins[len(bins) - 1]:
+            hist[len(hist) - 1] += 1
+
+    min_count = min(hist.values())
+    max_count = max(hist.values())
+
+    # `min_display_count` and `max_display_count` are the min/max
+    # counts that will be displayed on the x-axis of our
+    # graph. If the user sets the `regular` argument to True,
+    # we use a `min_display_count` of 0.
+    if regular:
+        min_display_count = 0
+    else:
+        min_display_count = min_count
+    max_display_count = max_count + 1
+
+    if width is None:
+        width = int(max_display_count - min_display_count)
+        if width > 40:
+            width = 40
+
+    # Calculate how many counts each horizontal unit (square)
+    # represents. This will be useful for knowing how long
+    # each of our bars should be.
+    counts_per_horizontal_unit = float(max_display_count - min_display_count) / width
+
+    # If we need to display y-labels, use `bins` to generate
+    # them. `ylabels_width` represents the width of the
+    # y-labels "column" so that we can add the appropriate
+    # amount of padding in the rest of our graph.
+    if ylab:
+        ylabels = [str(b) for b in bins]
+        ylabels_width = max(len(l) for l in ylabels) + 1
+    else:
+        ylabels_width = 0
+
+    # Print the title, as per usual
+    if title:
+        print(box_text(title, width*2 + ylabels_width))
+    print()
+
+    # Print the guts of the graph!
+    for bin_n, count in hist.iteritems():
+        line = ""
+        if ylab:
+            line += ylabels[bin_n].ljust(ylabels_width)
+        line += "|"
+
+        # This is why we calculated `counts_per_horizontal_unit`
+        # earlier.
+        n_squares = int((count - min_display_count) / counts_per_horizontal_unit) + 1
+        line += (" " + pch) * n_squares
+        print(line)
+
+    print(" " * ylabels_width + "+" + "-" * width * 2)
+
+    # Printing the x-labels is quite difficult. We only want to print
+    # a label for a square if it different to the previous label. This
+    # is because we don't want to print labels that look like
+    # "1 1 1 1 2 2 2 2...".
+    #
+    # We therefore generate a list of "candidate" x-labels, which are
+    # the labels we would show if we didn't care about repetition. We
+    # use this list of candidates to generate a list of deduplicated
+    # labels.
+    #
+    # First we generate the candidates
+    candidate_xlabels = [str(int(l)) for l in list(drange(
+        min_display_count,
+        max_display_count,
+        float(max_display_count - min_display_count) / width))]
+
+    # Then we deduplicate `candidate_xlabels`
+    xlabels = []
+    for cand in candidate_xlabels:
+        if cand not in xlabels:
+            xlabels.append(cand)
+        else:
+            xlabels.append("")
+
+    # Print the labels vertically by printing a row with all
+    # the first characters in each label, then a row with all
+    # the second characters, etc.
+    max_xlabel_len = max(len(l) for l in xlabels)
+    for row_n in range(0, max_xlabel_len):
+        row = ""
+        for label in xlabels:
+            if len(label) > row_n:
+                row += label[row_n]
+            else:
+                row += " "
+            row += " "
+        print(" " * (ylabels_width + 2) + row)
+
+    # Finally, print the summary statistics, as per usual
+    if show_summary:
+        center = max(map(len, map(str, [n, min_val, mean, max_val])))
+        center += 15
+
+        print()
+        print("-" * (2 + center))
+        print("|" + "Summary".center(center) + "|")
+        print("-" * (2 + center))
+        summary = "|" + ("observations: %d" % n).center(center) + "|\n"
+        summary += "|" + ("min value: %f" % min_val).center(center) + "|\n"
+        summary += "|" + ("mean : %f" % mean).center(center) + "|\n"
+        summary += "|" + ("std dev : %f" % sd).center(center) + "|\n"
+        summary += "|" + ("max value: %f" % max_val).center(center) + "|\n"
+        summary += "-" * (2 + center)
+        print(summary)
+
+
+def calc_bins(n, min_val, max_val, h=None, binwidth=None):
+    """
+    Calculate number of bins for the histogram
+    """
+    if not h:
+        h = max(10, math.log(n + 1, 2))
+    if binwidth == 0:
+        binwidth = 0.1
+    if binwidth is None:
+        binwidth = (max_val - min_val) / h
+    for b in drange(min_val, max_val, step=binwidth, include_stop=True):
+        if b.is_integer():
+            yield int(b)
+        else:
+            yield b
+
+
+def read_numbers(numbers):
+    """
+    Read the input data in the most optimal way
+    """
+    if isiterable(numbers):
+        for number in numbers:
+            yield float(str(number).strip())
+    else:
+        with open(numbers) as fh:
+            for number in fh:
+                yield float(number.strip())
+
+