Mini Shell

# vim: set fileencoding=utf-8 :
import math, os, re, string, sys

__all__ = ["guess_series", "main", "spark_chars", "sparkify"]

spark_chars = u"▁▂▃▄▅▆▇█"
"""Eight unicode characters of (nearly) steadily increasing height."""


def sparkify(series, minimum=None, maximum=None, rows=1):
    u"""Converts <series> to a sparkline string.

    Example:
    >>> sparkify([ 0.5, 1.2, 3.5, 7.3, 8.0, 12.5, float("nan"), 15.0, 14.2, 11.8, 6.1,
    ... 1.9 ])
    u'▁▁▂▄▅▇ ██▆▄▂'

    >>> sparkify([1, 1, -2, 3, -5, 8, -13])
    u'▆▆▅▆▄█▁'

    Raises ValueError if input data cannot be converted to float.
    Raises TypeError if series is not an iterable.
    """
    series = [float(n) for n in series]
    if all(not math.isfinite(n) for n in series):
        return u" " * len(series)

    minimum = min(filter(math.isfinite, series)) if minimum is None else minimum
    maximum = max(filter(math.isfinite, series)) if maximum is None else maximum
    data_range = maximum - minimum
    if data_range == 0.0:
        # Graph a baseline if every input value is equal.
        return u"".join([spark_chars[0] if math.isfinite(i) else u" " for i in series])
    row_res = len(spark_chars)
    resolution = row_res * rows
    coefficient = (resolution - 1.0) / data_range

    def clamp(n):
        return min(max(n, minimum), maximum)

    def spark_index(n):
        """An integer from 0 to (resolution-1) proportional to the data range"""
        return int(round((clamp(n) - minimum) * coefficient))

    output = []
    for r in range(rows - 1, -1, -1):
        row_out = []
        row_min = row_res * r
        row_max = row_min + row_res - 1
        for n in series:
            if not math.isfinite(n):
                row_out.append(" ")
                continue
            i = spark_index(n)
            if i < row_min:
                row_out.append(" ")
            elif i > row_max:
                row_out.append(spark_chars[-1])
            else:
                row_out.append(spark_chars[i % row_res])
        output.append(u"".join(row_out))
    return os.linesep.join(output)


def _convert_to_float(n):
    try:
        return float(n)
    except:
        return None


def guess_series(input_string):
    u"""Tries to convert <input_string> into a list of floats.

    Example:
    >>> guess_series("0.5 1.2 3.5 7.3 8 nan 12.5, 13.2,"
    ... "15.0, 14.2, 11.8, 6.1, 1.9")
    [0.5, 1.2, 3.5, 7.3, 8.0, nan, 12.5, 13.2, 15.0, 14.2, 11.8, 6.1, 1.9]
    """
    float_finder = re.compile(r"(nan|[-+]?[0-9]*\.?[0-9]+(?:e[-+]?[0-9]+)?)", re.I)
    return [
        i
        for i in [
            _convert_to_float(j)
            for j in float_finder.findall(input_string)
            # Remove entires we couldn't convert to a sensible value.
        ]
        if i is not None
    ]


def main():
    u"""Reads from command line args or stdin and prints a sparkline from the
    data.  Requires at least 2 data points as input.
    """
    import argparse
    from pkg_resources import require

    parser = argparse.ArgumentParser(description=main.__doc__)
    parser.add_argument("data", nargs="*", help="Floating point data, any delimiter.")
    parser.add_argument(
        "--version",
        "-v",
        action="store_true",
        help="Display the version number and exit.",
    )
    parser.add_argument("--min", type=float, help="Set smaller values to MIN.")
    parser.add_argument("--max", type=float, help="Set larger values to MAX.")
    parser.add_argument(
        "--rows",
        "-r",
        type=int,
        default=1,
        help="Number of rows high the graph will be.",
    )
    args = parser.parse_args()

    if args.version:
        version = require("pysparklines")[0].version
        print(version)
        sys.exit(0)

    if os.isatty(0) and not args.data:
        parser.print_help()
        sys.exit(1)
    elif args.data:
        arg_string = u" ".join(args.data)
    else:
        arg_string = sys.stdin.read()

    try:
        print(
            sparkify(
                guess_series(arg_string),
                minimum=args.min,
                maximum=args.max,
                rows=args.rows,
            )
        )
    except Exception:  # should be more specific, but better than a bare except clause
        sys.stderr.write("Could not convert input data to valid sparkline" + os.linesep)
        sys.exit(1)


if __name__ == "__main__":
    main()