almost final version of tutorial material

Author: tacaswell

.gitignore

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+__pycache__
+*.pyc
+*~

00-explore.py

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+import matplotlib.pyplot as plt
+import numpy as np
+plt.ion()
+
+ev = None
+
+
+def event_printer(event):
+    """Helper function for exploring events.
+
+    Prints all public attributes +
+    """
+    global ev
+    ev = event
+    for k, v in sorted(vars(event).items()):
+        print('{k}: {v!r}'.format(k=k, v=v))
+    print('-'*25)
+
+th = np.linspace(0, 2*np.pi, 64)
+fig, ax = plt.subplots()
+ax.plot(th, np.sin(th), 'o-', picker=5)
+
+cid = fig.canvas.mpl_connect('button_press_event', event_printer)
+# fig.canvas.mpl_disconnect(cid)
+
+
+# EXERCISE
+# - Try all 'active' events
+#   ['button_press_event', 'button_release_event', 'scroll_event',
+#    'key_press_event', 'key_release_event', 'pick_event']
+# - tweak the print line
+# - remove a callback
+# - add more than one callback to the canvas

01-callable.py

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+from collections import deque
+import matplotlib as mpl
+import matplotlib.pyplot as plt
+import numpy as np
+plt.ion()
+
+# disable the built in key bindings
+for k in ['keymap.all_axes',
+          'keymap.back',
+          'keymap.forward',
+          'keymap.fullscreen',
+          'keymap.grid',
+          'keymap.home',
+          'keymap.pan',
+          'keymap.save',
+          'keymap.xscale',
+          'keymap.yscale',
+          'keymap.zoom']:
+    mpl.rcParams[k] = []
+
+
+class EventCollector:
+    def __init__(self, maxlen=12):
+        self.event_deque = deque([], maxlen=maxlen)
+
+    def __call__(self, event):
+        print('called {} at ({}, {})'.format(event.name,
+                                             event.xdata,
+                                             event.ydata))
+        self.event_deque.append(event)
+
+
+fig, ax = plt.subplots()
+
+th = np.linspace(0, 2*np.pi, 64)
+ln, = ax.plot(th, np.sin(th), 'o-', picker=5)
+
+ec = EventCollector()
+cid = fig.canvas.mpl_connect('key_press_event', ec)
+
+
+# EXERCISE
+# - Try connecting the same object to events calls
+# - add helper function to manage event buffer

02-event_filter.py

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+import matplotlib.pyplot as plt
+from itertools import cycle
+plt.ion()
+
+
+class LineMaker:
+    def __init__(self, ln):
+        # stash the current data
+        self.xdata = list(ln.get_xdata())
+        self.ydata = list(ln.get_ydata())
+        # stash the Line2D artist
+        self.ln = ln
+        self.color_cyle = cycle(['#1f77b4', '#ff7f0e', '#2ca02c', '#d62728',
+                                 '#9467bd', '#8c564b', '#e377c2', '#7f7f7f',
+                                 '#bcbd22', '#17becf'])
+        self.button_cid = ln.figure.canvas.mpl_connect('button_press_event',
+                                                       self.on_button)
+        self.key_cid = ln.figure.canvas.mpl_connect('key_press_event',
+                                                    self.on_key)
+
+    def on_button(self, event):
+        # only consider events from the lines Axes
+        if event.inaxes is not self.ln.axes:
+            return
+
+        # if not the left mouse button or a modifier key
+        # is held down, bail
+        if event.button != 1 or event.key is not None:
+            print('key+button: {!r}+{!r}'.format(event.key, event.button))
+            return
+
+        # get the event location in data-space
+        self.xdata.append(event.xdata)
+        self.ydata.append(event.ydata)
+
+        # update the artist data
+        self.ln.set_data(self.xdata, self.ydata)
+
+        # ask the GUI to re-draw the next time it can
+        self.ln.figure.canvas.draw_idle()
+
+    def on_key(self, event):
+        # This is _super_ useful for debugging!
+        # print(event.key)
+
+        # if the key is c (any case)
+        if event.key.lower() == 'c':
+            # change the color
+            self.ln.set_color(next(self.color_cyle))
+
+            # ask the GUI to re-draw the next time it can
+            self.ln.figure.canvas.draw_idle()
+
+fig, ax = plt.subplots()
+ln, = ax.plot([], [], '-o')
+line_maker = LineMaker(ln)
+
+# EXERCISE
+# - modify to remove the closest point on button == 3 or key == 'shift'
+# - change the line width for [1-9]
+# - clear the line when event.key == 'escape'

03-picking.py

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+import matplotlib.pyplot as plt
+from pddc_helpers import (load_bwi_data, aggregate_by_day, extract_day_of_hourly,
+                          label_date)
+import uuid
+plt.ion()
+
+bwi = load_bwi_data()
+bwi = bwi[bwi['year'] > 2014]
+bwi_daily = aggregate_by_day(bwi)
+
+
+class RowPrinter:
+    def __init__(self, ln, df, picker=10):
+        ln.set_picker(picker)
+        self.uid = str(uuid.uuid4())
+        ln.set_gid(self.uid)
+        self.ln = ln
+        self.df = df
+        self.cid = None
+        self.connect()
+
+    def connect(self):
+        self.remove()
+        self.cid = ln.figure.canvas.mpl_connect('pick_event',
+                                                self)
+
+    def __call__(self, event):
+        # ignore picks on not-our-artist
+        if event.artist is not self.ln:
+            return
+        # for each hit index, print out the row
+        for i in event.ind:
+            print(self.df.iloc[i])
+
+    def remove(self):
+        if self.cid is not None:
+            self.ln.figure.canvas.mpl_disconnect(self.cid)
+            self.cid = None
+
+
+fig, ax = plt.subplots()
+ln, = ax.plot('mean', '-o', data=bwi_daily)
+ax.set_xlabel('Date [UTC]')
+ax.set_ylabel('Air Temperature [℃]')
+ax.set_title('BWI')
+rp = RowPrinter(ln, bwi_daily)
+
+one_day = extract_day_of_hourly(bwi, 2015, 10, 18)
+
+# EXERCISE
+# - make the print out nicer looking
+# - make picking add a label with `label_data`
+# - use `get_gid` to filter instead of `is not`
+# - open a new window with plot of day temperature
+#   - fig, ax = plt.subplots()
+#   - one_day = extract_day_of_hourly(bwi, 2015, 10, 18)

04-custom_plotting.py

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+import matplotlib.pyplot as plt
+from pddc_helpers import load_bwi_data, aggregate_by_month
+plt.ion()
+
+
+def plot_aggregated_errorbar(ax, gb, label, picker=None, **kwargs):
+    kwargs.setdefault('capsize', 3)
+    kwargs.setdefault('markersize', 5)
+    kwargs.setdefault('marker', 'o')
+    eb = ax.errorbar(gb.index, 'mean',
+                     yerr='std',
+                     data=gb,
+                     label=label,
+                     picker=picker,
+                     **kwargs)
+    fill = ax.fill_between(gb.index, 'min', 'max', alpha=.5,
+                           data=gb, color=eb[0].get_color())
+    ax.legend()
+    ax.figure.canvas.draw_idle()
+    return eb, fill
+
+bwi = load_bwi_data()
+bwi_monthly = aggregate_by_month(bwi)
+
+fig, ax = plt.subplots()
+ax.set_xlabel('Date [UTC]')
+ax.set_ylabel('Air Temperature [℃]')
+ax.set_title('BWI')
+
+arts = plot_aggregated_errorbar(ax, bwi_monthly, 'bwi')