当年学matplotlib半途而废了。。。
现如今决定重新拾起来，在此立个flag，每日记录一个主题，一方面督促自己坚持下去，另一方面方便将来用的时候查阅。

Subplot

1. subplot 方法

np.random.seed(19680801)

dt = 0.01
t = np.arange(0, 10, dt)
nse = np.random.randn(len(t))
r = np.exp(-t / 0.05)

cnse = np.convolve(nse, r) * dt
cnse = cnse[:len(t)]
s = 0.1 * np.sin(2 * np.pi * t) + cnse

fig, ax_lst = plt.subplots(2,1)
# plt.subplot(211)
ax_lst[0].plot(t, s)
# plt.subplot(212)
ax_lst[1].psd(s, 512, 1 / dt)

plt.show()

image.png

调整子图间距

fig, axes = plt.subplots(2, 2, sharex=True, sharey=True)
for i in range(2):
    for j in range(2):
        axes[i, j].hist(np.random.randn(500), bins=50, color='k', alpha=0.5)
plt.subplots_adjust(wspace=0, hspace=0)

image.png

2. GridSpec 方法

a flexible way to layout subplot grids. Specifies the geometry of the grid that a subplot can be placed in

def format_axes(fig):
    for i, ax in enumerate(fig.axes):
        ax.text(0.5, 0.5, "ax%d" % (i+1), va="center", ha="center")
        ax.tick_params(labelbottom=False, labelleft=False)

fig = plt.figure(constrained_layout=True)

gs = GridSpec(3, 3, figure=fig)
ax1 = fig.add_subplot(gs[0, :])
# identical to ax1 = plt.subplot(gs.new_subplotspec((0, 0), colspan=3))
ax2 = fig.add_subplot(gs[1, :-1])
ax3 = fig.add_subplot(gs[1:, -1])
ax4 = fig.add_subplot(gs[-1, 0])
ax5 = fig.add_subplot(gs[-1, -2])

fig.suptitle("GridSpec")
format_axes(fig)

plt.show()

image.png

Nested GridSpec

def format_axes(fig):
    for i, ax in enumerate(fig.axes):
        ax.text(0.5, 0.5, "ax%d" % (i+1), va="center", ha="center")
        ax.tick_params(labelbottom=False, labelleft=False)


# gridspec inside gridspec
f = plt.figure()

gs0 = gridspec.GridSpec(1, 2, figure=f)

gs00 = gridspec.GridSpecFromSubplotSpec(3, 3, subplot_spec=gs0[0])

ax1 = f.add_subplot(gs00[:2, :])
ax2 = f.add_subplot(gs00[2, :2])
ax3 = f.add_subplot(gs00[2, 2])

# the following syntax does the same as the GridSpecFromSubplotSpec call above:
gs01 = gs0[1].subgridspec(3, 3)

ax4 = f.add_subplot(gs01[:, :-1])
ax5 = f.add_subplot(gs01[:-1, -1])
ax6 = f.add_subplot(gs01[-1, -1])

plt.suptitle("GridSpec Inside GridSpec")
format_axes(f)

plt.show()

image.png

3. 自定义方法

left, width = 0.1, 0.65
bottom, height = 0.1, 0.65
spacing = 0.005


rect_scatter = [left, bottom, width, height]
rect_histx = [left, bottom + height + spacing, width, 0.2]
rect_histy = [left + width + spacing, bottom, 0.2, height]

# start with a rectangular Figure
fig = plt.figure(figsize=(8, 8))

ax_scatter = fig.add_axes(rect_scatter)
ax_scatter.tick_params(direction='in', top=True, right=True)
ax_histx = fig.add_axes(rect_histx)
ax_histx.tick_params(direction='in', labelbottom=False)
ax_histy = fig.add_axes(rect_histy)
ax_histy.tick_params(direction='in', labelleft=False)

image.png

很多看起来比较复杂高级的图形都是通过几种基本图形组合而来的，掌握了以上这几种方法，基本可以满足日常作图的需求了，根据实际需要自由安排。