Uniplot

Lightweight plotting to the terminal. 4x resolution via Unicode.

When working with production data science code it can be handy to have plotting tool that does not rely on graphics dependencies or works only in a Jupyter notebook.

The use case that this was built for is to have plots as part of your data science / machine learning CI/CD pipeline - that way whenever something goes wrong, you get not only the error and backtrace but also plots that show what the problem was.

Features

• Unicode drawing, so 4x the resolution (pixels) of usual ASCII plots
• Super simple API
• Interactive mode (pass interactive=True)
• Color mode (pass color=True) useful in particular when plotting multiple series
• It's fast: Plotting 1M data points takes 100ms thanks to NumPy magic
• Only one dependency: NumPy (but you have that anyway don't you)

Please note that Unicode drawing will work correctly only when using a font that fully supports the Block Elements character set or the Braille character set. Please refer to this page for a (incomplete) list of supported fonts and the options below to select the character set.

Simple example

import math
x = [math.sin(i/20)+i/300 for i in range(600)]
from uniplot import plot
plot(x, title="Sine wave")

Result:

                          Sine wave
┌────────────────────────────────────────────────────────────┐
│                                                    ▟▀▚     │
│                                                   ▗▘ ▝▌    │
│                                       ▗▛▜▖        ▞   ▐    │
│                                       ▞  ▜       ▗▌    ▌   │ 2
│                           ▟▀▙        ▗▘  ▝▌      ▐     ▜   │
│                          ▐▘ ▝▖       ▞    ▜      ▌     ▝▌  │
│              ▗▛▜▖        ▛   ▜      ▗▌    ▝▌    ▐▘      ▜  │
│              ▛  ▙       ▗▘   ▝▖     ▐      ▚    ▞       ▝▌ │
│  ▟▀▖        ▐▘  ▝▖      ▟     ▚     ▌      ▝▖  ▗▌        ▜▄│ 1
│ ▐▘ ▐▖       ▛    ▙      ▌     ▐▖   ▗▘       ▚  ▞           │
│ ▛   ▙      ▗▘    ▐▖    ▐       ▙   ▞        ▝▙▟▘           │
│▐▘   ▐▖     ▐      ▌    ▛       ▐▖ ▗▘                       │
│▞     ▌     ▌      ▐   ▗▘        ▜▄▛                        │
│▌─────▐────▐▘───────▙──▞────────────────────────────────────│ 0
│       ▌   ▛        ▝▙▟▘                                    │
│       ▜  ▐▘                                                │
│        ▙▄▛                                                 │
└────────────────────────────────────────────────────────────┘
         100       200       300       400       500       600

For more examples, please see the examples/ folder.

Parameters

The plot function accepts a number of parameters, all listed below. Note that only ys is required, all others are optional.

There is also a plot_to_string function with the same signature, if you want the result as a list of strings, to include the output elsewhere. The only difference is that plot_to_string does not support interactive mode.

Data

• xs - The x coordinates of the points to plot. Can either be None, or a list or NumPy array for plotting a single series, or a list of those for plotting multiple series. Defaults to None, meaning that the x axis will be just the sample index of ys.
• ys - The y coordinates of the points to plot. Can either be a list or NumPy array for plotting a single series, or a list of those for plotting multiple series.

In both cases, NaN or None values are ignored.

Note that since v0.12.0 you can also pass a list or an NumPy array of timestamps, and the axis labels should be formatted correctly.

Options

In alphabetical order:

Basic options

• color - Draw series in color. Defaults to False when plotting a single series, and to True when plotting multiple. Also accepts a list of strings, to modify the default order of ["blue", "magenta", "green", "yellow", "cyan", "red"].
• height - The height of the plotting region, in characters. Default is 17.
• interactive - Enable interactive mode. Defaults to False.
• legend_labels - Labels for the series. Can be None or a list of strings. Defaults to None.
• lines - Enable lines between points. Can either be True or False, or a list of Boolean values for plotting multiple series. Defaults to False.
• title - The title of the plot. Defaults to None.
• width - The width of the plotting region, in characters. Default is 60. Note that if the line_length_hard_cap option (see "Advanced options" below) is used and there is not enough space, the actual width may be smaller.
• x_max - Maximum x value of the view. Defaults to a value that shows all data points.
• x_min - Minimum x value of the view. Defaults to a value that shows all data points.
• x_unit - Unit of the x axis. This is a string that is appended to the axis labels. Defaults to "".
• y_max - Maximum y value of the view. Defaults to a value that shows all data points.
• y_min - Minimum y value of the view. Defaults to a value that shows all data points.
• y_unit - Unit of the y axis. This is a string that is appended to the axis labels. Defaults to "".

Advanced options

• character_set - Which Unicode character set to use. Use "block" for the Block Elements character set with 4x resolution, or "braille" for the Braille character set with 8x resolution. The latter has a lighter look overall. Defaults to "block".
• force_ascii - Force ASCII characters for plotting only. This can be useful for compatibility, for example when using uniplot inside of CI/CD systems that do not support Unicode. Defaults to False.
• force_ascii_characters - List of characters to use when plotting in force_ascii mode. Default to ["+", "x", "o", "*", "~", "."].
• line_length_hard_cap - Enforce a hard limit on the number of characters per line of the plot area. This may override the width option if there is not enough space. Defaults to None.
• x_as_log - Plot the x axis as logarithmic scale. Defaults to False.
• x_gridlines - A list of x values that have a vertical line for better orientation. Defaults to [0], or to [] if x_as_log is enabled.
• y_as_log - Plot the y axis as logarithmic scale. Defaults to False.
• y_gridlines - A list of y values that have a horizontal line for better orientation. Defaults to [0], or to [] if y_as_log is enabled.

Changing default parameters

uniplot does not store a state of the configuration parameters. However, you can define a new plot funtion with new defaults by defining a partial. See the following example:

from functools import partial
from uniplot import plot as default_plot
plot = partial(default_plot, height=25, width=80)

This defines a new plot function that is identical to the original, except the default values for width and height are now different.

Experimental features

Plotting histograms

For convenience there is also a histogram function that accepts one or more series and plots bar-chart like histograms. It will automatically discretize the series into a number of bins given by the bins option and display the result.

Additional options, in alphabetical order:

• bins - Number of bins to use. Defaults to 20.
• bins_min - Lower limit of the first bin. Defaults to the minimum of the series.
• bins_max - Upper limit of the last bin. Defaults to the maximum of the series.

When calling the histogram function, the lines option is True by default.

Example:

import numpy as np
x = np.sin(np.linspace(1, 1000))
from uniplot import histogram
histogram(x)

Result:

┌────────────────────────────────────────────────────────────┐
│   ▛▀▀▌                       │                   ▐▀▀▜      │ 5
│   ▌  ▌                       │                   ▐  ▐      │
│   ▌  ▌                       │                   ▐  ▐      │
│   ▌  ▀▀▀▌                    │                ▐▀▀▀  ▝▀▀▜   │
│   ▌     ▌                    │                ▐        ▐   │
│   ▌     ▌                    │                ▐        ▐   │
│   ▌     ▙▄▄▄▄▄▖              │          ▗▄▄▄  ▐        ▐   │
│   ▌           ▌              │          ▐  ▐  ▐        ▐   │
│   ▌           ▌              │          ▐  ▐  ▐        ▐   │
│   ▌           ▌              │          ▐  ▐  ▐        ▐   │
│   ▌           ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▜  ▐▀▀▀  ▝▀▀▀        ▐   │
│   ▌                          │    ▐  ▐                 ▐   │
│   ▌                          │    ▐  ▐                 ▐   │
│   ▌                          │    ▐▄▄▟                 ▐   │
│   ▌                          │                         ▐   │
│   ▌                          │                         ▐   │
│▄▄▄▌▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁│▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▐▄▄▄│ 0
└────────────────────────────────────────────────────────────┘
     -1                        0                       1

Streaming

There is initial support for streaming using the plot_gen function. The idea is have a class that wraps the plot function and the state of plotting, such that we can update the state of the plot.

Example, assuming we had a function called get_new_data to get new data from some source:

from uniplot import plot_gen

plt = plot_gen()
ys = []

while True:
    ys.append(get_new_data())
    plt.update(ys=ys, title=f"Streaming: {len(ys)} data point(s) ...")

See examples/5-sreaming.py for a more complete example.

Installation

Install via pip using:

pip install uniplot

Contributing

Clone this repository, and install dependecies via poetry install.

You can run the tests via poetry run ./run_tests to make sure your setup is good. Then proceed with issues, PRs etc. the usual way.