four_sided_plot

Example Python program four_sided_plot.py

Modules

• import numpy as np
• from matplotlib import pyplot as plt

Code

Python example

import numpy as np
from matplotlib import pyplot as plt

# Generate fake data
np.random.seed(123)
wavelen = np.arange(500, 1000, 8)
fluxden = -wavelen**2/1000 + 2*wavelen + np.random.normal(loc=0, scale=5, size=len(wavelen))
fluxerr = np.sqrt(fluxden)

# Default plot with errorbars
fig, ax = plt.subplots(nrows=1, ncols=1)
ax.errorbar(wavelen, fluxden, yerr=fluxerr, marker='.', ls=':', capsize=3)

################################################################################
# Simple answer
################################################################################
ax.tick_params(axis='both',                    # Which axis ('x', 'y', 'both')
               direction='in',                 # Which direction ('in', 'out', 'inout')
               top=True, bottom=True,          # Whether to show ticks on top, bot, left, right
               left=True, right=True,
               labeltop=True, labelbottom=True, # Whether to show labels on top, etc
               labelleft=True, labelright=True)
# REF: https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.tick_params.html

plt.show()


################################################################################
# A bit complicated answer
################################################################################
# Default plot with errorbars
fig, ax = plt.subplots(nrows=1, ncols=1)
ax.errorbar(wavelen, fluxden, yerr=fluxerr, marker='.', ls=':', capsize=3)

# Make ticks to the inside at all 4 axes
alltick = dict(top=True, bottom=True, left=True, right=True,                     # Whether to show ticks
               labeltop=True, labelbottom=True, labelleft=True, labelright=True) # Whether to show labels

ax.tick_params(axis='both',    # Which axis ('x', 'y', 'both')
               direction='in', # Which direction ('in', 'out', 'inout')
               length=5,       # Tick length
               width=2,        # Tick width
               color='b',      # Tick color ('k' for black, etc)
               pad=10,         # Tick & label distance
               **alltick)
# REF: https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.tick_params.html
# INFO: ``**alltick`` is identical to directly put ``top=Ture, bottom=True, .....`` in this case.

# Put grid
ax.grid(ls=':')

# x-axis: "wavelength" with blue color
ax.set_xlabel("Wavelength [nm]", color='b')
ax.tick_params(axis='x', colors='b')

# y-axis: "intensity" with green color
ax.set_ylabel("Intensity [arbitrary]", color='g')
ax.tick_params(axis='y', colors='g')

# Put title
ax.set_title(r"LaTeX Style title: $F=ma$", y=1.1)

plt.show()

Useful Links

• Articles: https://python-commandments.org/
• Python shell: https://bsdnerds.org/learn-python/
• Tutorial: https://pythonprogramminglanguage.com/