Python histogramming

histogram.py

def histogram(nums, n_buckets, title):
    min_val = min(*nums)
    max_val = max(*nums)
    buckets = []
    bucket_width = (max_val - min_val) / float(n_buckets)
    while (len(buckets) < n_buckets):
        buckets.append(0)
    sum_of_values = 0
    for num in nums:
        sum_of_values += num
        bucket_idx = max(0, min(n_buckets - 1, int((num - min_val) / bucket_width)))
        buckets[bucket_idx] += 1

    bucket_labels = [
        '[%.02g, %.02g)' % (min_val + i * bucket_width, min_val + (i + 1) * bucket_width)
        for i in range(0, n_buckets)
    ]

    label_column_width = max(*[len(lbl) for lbl in bucket_labels])

    histogram_lines = []

    n_text_columns = 75
    max_count = max(*[buckets])

    # Header line like '### TITLE ###'
    left_pad = (n_text_columns - len(title) - 2) // 2
    histogram_lines.append(
        f'{"#" * left_pad} {title} {"#" * (n_text_columns - len(title) - 2 - left_pad)}'
    )
    total = 0
    for i in range(0, n_buckets):
        bucket_label = bucket_labels[i]
        count = buckets[i]
        total += count
        line = ' ' * (label_column_width - len(bucket_label))
        line += bucket_label
        line += ': '
        bar_width = (count / max_count) * 45.0
        line += '▄' * int(bar_width)
        if bar_width > int(bar_width):
            line += '▖'
        line += ' (%s)' % count
        histogram_lines.append(line)
    average = sum_of_values / total
    histogram_lines.append('Total: %d, mean: %0.2g' % (total, average))
    return '\n'.join(histogram_lines)