matplotlib.github.com/2.2.2/tutorials/text/text_intro.html at main · matplotlib/matplotlib.github.com

History

622 lines (567 loc) · 83.3 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<head>

<title>Text in Matplotlib Plots — Matplotlib 2.2.2 documentation</title>

type="text/css" />

type="text/css" />

var DOCUMENTATION_OPTIONS = {

URL_ROOT: '../../',

VERSION: '2.2.2',

COLLAPSE_INDEX: false,

FILE_SUFFIX: '.html',

HAS_SOURCE: true,

SOURCELINK_SUFFIX: '.txt'

};

</script>

title="Search within Matplotlib 2.2.2 documentation"

href="../../_static/opensearch.xml"/>

</head>

<body>

<div id="unreleased-message"> You are reading an old version of the documentation (v2.2.2). For the latest version see <a href="https://matplotlib.org/stable/tutorials/text/text_intro.html">https://matplotlib.org/stable/tutorials/text/text_intro.html</a></div>

<div style="float: left; position: absolute; width: 496px; bottom: 0; padding-bottom: 24px">Version 2.2.2</div>

<div id="forkongithub"><a href="https://github.com/matplotlib/matplotlib">Fork me on GitHub</a></div>

</div>

<h3>Navigation</h3>

<ul>

<a href="../../genindex.html" title="General Index"

accesskey="I">index</a></li>

<a href="../../py-modindex.html" title="Python Module Index"

>modules</a> |</li>

<a href="../toolkits/mplot3d.html" title="The mplot3d Toolkit"

accesskey="N">next</a> |</li>

<a href="text_props.html" title="Text properties and layout"

accesskey="P">previous</a> |</li>

<li><a href="../../gallery/index.html">examples</a>| </li>

<li><a href="../index.html">tutorials</a>| </li>

<li><a href="../../api/pyplot_summary.html">pyplot</a>| </li>

<li><a href="../../users/index.html" >User’s Guide</a> »</li>

<li><a href="../index.html" accesskey="U">Tutorials</a> »</li>

</ul>

</div>

<h3>Quick search</h3>

</form>

</div>

<h3><a href="../../contents.html">Table Of Contents</a></h3>

<ul>

<li><a class="reference internal" href="#">Text in Matplotlib Plots</a><ul>

<li><a class="reference internal" href="#basic-text-commands">Basic text commands</a></li>

<li><a class="reference internal" href="#labels-for-x-and-y-axis">Labels for x- and y-axis</a></li>

<li><a class="reference internal" href="#titles">Titles</a></li>

<li><a class="reference internal" href="#ticks-and-ticklabels">Ticks and ticklabels</a><ul>

<li><a class="reference internal" href="#terminology">Terminology</a></li>

<li><a class="reference internal" href="#simple-ticks">Simple ticks</a></li>

<li><a class="reference internal" href="#tick-locators-and-formatters">Tick Locators and Formatters</a></li>

<li><a class="reference internal" href="#dateticks">Dateticks</a></li>

</ul>

</li>

<li><a class="reference internal" href="#legends-and-annotations">Legends and Annotations</a></li>

</ul>

</li>

</ul>

<h3>Related Topics</h3>

<ul>

<li><a href="../../contents.html">Documentation overview</a><ul>

<li><a href="../../users/index.html">User’s Guide</a><ul>

<li><a href="../index.html">Tutorials</a><ul>

<li>Previous: <a href="text_props.html" title="previous chapter">Text properties and layout</a></li>

<li>Next: <a href="../toolkits/mplot3d.html" title="next chapter">The mplot3d Toolkit</a></li>

</ul></li>

</ul>

</div>

<div id="sidebar-pagesource" role="note" aria-label="source link"

style="margin-top: 1.5em; padding-top: 0.1em; border-top: 1px solid #86989b">

<a href="../../_sources/tutorials/text/text_intro.rst.txt"

style="color: #c0c0c0" rel="nofollow">Show Page Source</a>

</div>

Note

Click <a class="reference internal" href="#sphx-glr-download-tutorials-text-text-intro-py">here</a> to download the full example code

</div>

<h1>Text in Matplotlib Plots<a class="headerlink" href="#text-in-matplotlib-plots" title="Permalink to this headline">¶</a></h1>

Introduction to plotting and working with text in Matplotlib.

Matplotlib has extensive text support, including support for

mathematical expressions, truetype support for raster and

vector outputs, newline separated text with arbitrary

rotations, and unicode support.

Because it embeds fonts directly in output documents, e.g., for postscript

or PDF, what you see on the screen is what you get in the hardcopy.

<a class="reference external" href="https://www.freetype.org/">FreeType</a> support

produces very nice, antialiased fonts, that look good even at small

raster sizes. matplotlib includes its own

<a class="reference internal" href="../../api/font_manager_api.html#module-matplotlib.font_manager" title="matplotlib.font_manager"><code class="xref py py-mod docutils literal notranslate">matplotlib.font_manager</code></a> (thanks to Paul Barrett), which

implements a cross platform, <code class="xref py py-obj docutils literal notranslate">W3C</code>

compliant font finding algorithm.

The user has a great deal of control over text properties (font size, font

weight, text location and color, etc.) with sensible defaults set in

the <code class="xref py py-obj docutils literal notranslate">rc file</code>.

And significantly, for those interested in mathematical

or scientific figures, matplotlib implements a large number of TeX

math symbols and commands, supporting <a class="reference internal" href="mathtext.html#sphx-glr-tutorials-text-mathtext-py">mathematical expressions</a> anywhere in your figure.

<h2>Basic text commands<a class="headerlink" href="#basic-text-commands" title="Permalink to this headline">¶</a></h2>

The following commands are used to create text in the pyplot

interface and the object-oriented API:

</colgroup>

<tr class="row-odd"><th class="head"><a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.html#module-matplotlib.pyplot" title="matplotlib.pyplot"><code class="xref py py-obj docutils literal notranslate">pyplot</code></a> API</th>

<th class="head">description</th>

</tr>

</thead>

<td>Add text at an arbitrary location of

the <a class="reference internal" href="../../api/axes_api.html#matplotlib.axes.Axes" title="matplotlib.axes.Axes"><code class="xref py py-obj docutils literal notranslate">Axes</code></a>.</td>

</tr>

<tr class="row-odd"><td><a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.annotate.html#matplotlib.pyplot.annotate" title="matplotlib.pyplot.annotate"><code class="xref py py-obj docutils literal notranslate">annotate</code></a></td>

<td><a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.annotate.html#matplotlib.axes.Axes.annotate" title="matplotlib.axes.Axes.annotate"><code class="xref py py-obj docutils literal notranslate">annotate</code></a></td>

<td>Add an annotation, with an optional

arrow, at an arbitrary location of the

</tr>

<tr class="row-even"><td><a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.xlabel.html#matplotlib.pyplot.xlabel" title="matplotlib.pyplot.xlabel"><code class="xref py py-obj docutils literal notranslate">xlabel</code></a></td>

<td><a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.set_xlabel.html#matplotlib.axes.Axes.set_xlabel" title="matplotlib.axes.Axes.set_xlabel"><code class="xref py py-obj docutils literal notranslate">set_xlabel</code></a></td>

<td>Add a label to the <a class="reference internal" href="../../api/axes_api.html#matplotlib.axes.Axes" title="matplotlib.axes.Axes"><code class="xref py py-obj docutils literal notranslate">Axes</code></a>’s x-axis.</td>

</tr>

<tr class="row-odd"><td><a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.ylabel.html#matplotlib.pyplot.ylabel" title="matplotlib.pyplot.ylabel"><code class="xref py py-obj docutils literal notranslate">ylabel</code></a></td>

<td><a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.set_ylabel.html#matplotlib.axes.Axes.set_ylabel" title="matplotlib.axes.Axes.set_ylabel"><code class="xref py py-obj docutils literal notranslate">set_ylabel</code></a></td>

</tr>

<tr class="row-even"><td><a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.title.html#matplotlib.pyplot.title" title="matplotlib.pyplot.title"><code class="xref py py-obj docutils literal notranslate">title</code></a></td>

<td><a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.set_title.html#matplotlib.axes.Axes.set_title" title="matplotlib.axes.Axes.set_title"><code class="xref py py-obj docutils literal notranslate">set_title</code></a></td>

<td>Add a title to the <a class="reference internal" href="../../api/axes_api.html#matplotlib.axes.Axes" title="matplotlib.axes.Axes"><code class="xref py py-obj docutils literal notranslate">Axes</code></a>.</td>

</tr>

<tr class="row-odd"><td><a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.figtext.html#matplotlib.pyplot.figtext" title="matplotlib.pyplot.figtext"><code class="xref py py-obj docutils literal notranslate">figtext</code></a></td>

<td>Add text at an arbitrary location of

the <a class="reference internal" href="../../api/_as_gen/matplotlib.figure.Figure.html#matplotlib.figure.Figure" title="matplotlib.figure.Figure"><code class="xref py py-obj docutils literal notranslate">Figure</code></a>.</td>

</tr>

<tr class="row-even"><td><a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.suptitle.html#matplotlib.pyplot.suptitle" title="matplotlib.pyplot.suptitle"><code class="xref py py-obj docutils literal notranslate">suptitle</code></a></td>

<td><a class="reference internal" href="../../api/_as_gen/matplotlib.figure.Figure.html#matplotlib.figure.Figure.suptitle" title="matplotlib.figure.Figure.suptitle"><code class="xref py py-obj docutils literal notranslate">suptitle</code></a></td>

<td>Add a title to the <a class="reference internal" href="../../api/_as_gen/matplotlib.figure.Figure.html#matplotlib.figure.Figure" title="matplotlib.figure.Figure"><code class="xref py py-obj docutils literal notranslate">Figure</code></a>.</td>

</tr>

</tbody>

</table>

All of these functions create and return a <a class="reference internal" href="../../api/text_api.html#matplotlib.text.Text" title="matplotlib.text.Text"><code class="xref py py-obj docutils literal notranslate">Text</code></a> instance, which can be

configured with a variety of font and other properties. The example below

shows all of these commands in action, and more detail is provided in the

sections that follow.

<div class="highlight-python notranslate"><div class="highlight"><pre>import matplotlib

import matplotlib.pyplot as plt

fig = <a href="../../api/_as_gen/matplotlib.pyplot.figure.html#matplotlib.pyplot.figure" title="View documentation for matplotlib.pyplot.figure">plt.figure</a>()

fig.suptitle('bold figure suptitle', fontsize=14, fontweight='bold')

ax = fig.add_subplot(111)

fig.subplots_adjust(top=0.85)

ax.set_title('axes title')

ax.set_xlabel('xlabel')

ax.set_ylabel('ylabel')

ax.text(3, 8, 'boxed italics text in data coords', style='italic',

bbox={'facecolor': 'red', 'alpha': 0.5, 'pad': 10})

ax.text(2, 6, r'an equation: $E=mc^2$', fontsize=15)

ax.text(3, 2, u'unicode: Institut für Festkörperphysik')

ax.text(0.95, 0.01, 'colored text in axes coords',

verticalalignment='bottom', horizontalalignment='right',

transform=ax.transAxes,

color='green', fontsize=15)

ax.plot([2], [1], 'o')

ax.annotate('annotate', xy=(2, 1), xytext=(3, 4),

arrowprops=dict(facecolor='black', shrink=0.05))

ax.axis([0, 10, 0, 10])

<a href="../../api/_as_gen/matplotlib.pyplot.show.html#matplotlib.pyplot.show" title="View documentation for matplotlib.pyplot.show">plt.show</a>()

</pre></div>

</div>

</div>

<h2>Labels for x- and y-axis<a class="headerlink" href="#labels-for-x-and-y-axis" title="Permalink to this headline">¶</a></h2>

Specifying the labels for the x- and y-axis is strightforward, via the

<a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.set_xlabel.html#matplotlib.axes.Axes.set_xlabel" title="matplotlib.axes.Axes.set_xlabel"><code class="xref py py-obj docutils literal notranslate">set_xlabel</code></a> and

<a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.set_ylabel.html#matplotlib.axes.Axes.set_ylabel" title="matplotlib.axes.Axes.set_ylabel"><code class="xref py py-obj docutils literal notranslate">set_ylabel</code></a> methods.

<div class="highlight-python notranslate"><div class="highlight"><pre>import matplotlib.pyplot as plt

import numpy as np

x1 = <a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.linspace.html#numpy.linspace" title="View documentation for numpy.linspace">np.linspace</a>(0.0, 5.0, 100)

y1 = <a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.cos.html#numpy.cos" title="View documentation for numpy.cos">np.cos</a>(2 * np.pi * x1) * <a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.exp.html#numpy.exp" title="View documentation for numpy.exp">np.exp</a>(-x1)

fig, ax = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(figsize=(5, 3))

fig.subplots_adjust(bottom=0.15, left=0.2)

ax.plot(x1, y1)

ax.set_xlabel('time [s]')

ax.set_ylabel('Damped oscillation [V]')

</pre></div>

</div>

The x- and y-labels are automatically placed so that they clear the x- and

y-ticklabels. Compare the plot below with that above, and note the y-label

is to the left of the one above.

<div class="highlight-python notranslate"><div class="highlight"><pre>fig, ax = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(figsize=(5, 3))

ax.plot(x1, y1*10000)

ax.set_xlabel('time [s]')

ax.set_ylabel('Damped oscillation [V]')

</pre></div>

</div>

If you want to move the labels, you can specify the labelpad kyeword

argument, where the value is points (1/72”, the same unit used to specify

fontsizes).

ax.set_xlabel('time [s]')

ax.set_ylabel('Damped oscillation [V]', labelpad=18)

</pre></div>

</div>

Or, the labels accept all the <a class="reference internal" href="../../api/text_api.html#matplotlib.text.Text" title="matplotlib.text.Text"><code class="xref py py-obj docutils literal notranslate">Text</code></a> keyword arguments, including

position, via which we can manually specify the label positions. Here we

put the xlabel to the far left of the axis. Note, that the y-coordinate of

this position has no effect - to adjust the y-position we need to use the

labelpad kwarg.

ax.plot(x1, y1)

ax.set_xlabel('time [s]', position=(0., 1e6),

horizontalalignment='left')

ax.set_ylabel('Damped oscillation [V]')

</pre></div>

</div>

All the labelling in this tutorial can be changed by manipulating the

<a class="reference internal" href="../../api/font_manager_api.html#matplotlib.font_manager.FontProperties" title="matplotlib.font_manager.FontProperties"><code class="xref py py-obj docutils literal notranslate">matplotlib.font_manager.FontProperties</code></a> method, or by named kwargs to

<div class="highlight-python notranslate"><div class="highlight"><pre>from matplotlib.font_manager import <a href="../../api/font_manager_api.html#matplotlib.font_manager.FontProperties" title="View documentation for matplotlib.font_manager.FontProperties">FontProperties</a>

font = <a href="../../api/font_manager_api.html#matplotlib.font_manager.FontProperties" title="View documentation for matplotlib.font_manager.FontProperties">FontProperties</a>()

font.set_family('serif')

font.set_name('Times New Roman')

font.set_style('italic')

ax.plot(x1, y1)

ax.set_xlabel('time [s]', fontsize='large', fontweight='bold')

ax.set_ylabel('Damped oscillation [V]', fontproperties=font)

</pre></div>

</div>

Finally, we can use native TeX rendering in all text objects and have

multiple lines:

fig.subplots_adjust(bottom=0.2, left=0.2)

ax.plot(x1, <a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.cumsum.html#numpy.cumsum" title="View documentation for numpy.cumsum">np.cumsum</a>(y1**2))

ax.set_xlabel('time [s] \n This was a long experiment')

ax.set_ylabel(r'$\int\ Y^2\ dt\ \ [V^2 s]$')

</pre></div>

</div>

</div>

<h2>Titles<a class="headerlink" href="#titles" title="Permalink to this headline">¶</a></h2>

Subplot titles are set in much the same way as labels, but there is

the loc keyword arguments that can change the position and justification

from the default value of <code class="docutils literal notranslate">loc=center</code>.

<div class="highlight-python notranslate"><div class="highlight"><pre>fig, axs = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(3, 1, figsize=(5, 6), tight_layout=True)

locs = ['center', 'left', 'right']

for ax, loc in zip(axs, locs):

ax.plot(x1, y1)

ax.set_title('Title with loc at '+loc, loc=loc)

</pre></div>

</div>

Vertical spacing for titles is controlled via <code class="docutils literal notranslate">rcParams[axes.titlepad]</code>,

which defaults to 5 points. Setting to a different value moves the title.

ax.plot(x1, y1)

ax.set_title('Vertically offset title', pad=30)

</pre></div>

</div>

</div>

<h2>Ticks and ticklabels<a class="headerlink" href="#ticks-and-ticklabels" title="Permalink to this headline">¶</a></h2>

Placing ticks and ticklabels is a very tricky aspect of making a figure.

Matplotlib does the best it can automatically, but it also offers a very

flexible framework for determining the choices for tick locations, and

how they are labelled.

<h3>Terminology<a class="headerlink" href="#terminology" title="Permalink to this headline">¶</a></h3>

Axes have an <a class="reference internal" href="../../api/axis_api.html#module-matplotlib.axis" title="matplotlib.axis"><code class="xref py py-obj docutils literal notranslate">matplotlib.axis</code></a> object for the <code class="docutils literal notranslate">ax.xaxis</code>

and <code class="docutils literal notranslate">ax.yaxis</code> that

contain the information about how the labels in the axis are laid out.

The axis API is explained in detail in the documentation to

<a class="reference internal" href="../../api/axis_api.html#module-matplotlib.axis" title="matplotlib.axis"><code class="xref py py-obj docutils literal notranslate">axis</code></a>.

An Axis object has major and minor ticks. The Axis has a

<code class="xref py py-obj docutils literal notranslate">matplotlib.xaxis.set_major_locator</code> and

<code class="xref py py-obj docutils literal notranslate">matplotlib.xaxis.set_minor_locator</code> methods that use the data being plotted

to determine

the location of major and minor ticks. There are also

<code class="xref py py-obj docutils literal notranslate">matplotlib.xaxis.set_major_formatter</code> and

<code class="xref py py-obj docutils literal notranslate">matplotlib.xaxis.set_minor_formatters</code> methods that format the tick labels.

</div>

<h3>Simple ticks<a class="headerlink" href="#simple-ticks" title="Permalink to this headline">¶</a></h3>

It often is convenient to simply define the

tick values, and sometimes the tick labels, overriding the default

locators and formatters. This is discouraged because it breaks itneractive

navigation of the plot. It also can reset the axis limits: note that

the second plot has the ticks we asked for, including ones that are

well outside the automatic view limits.

<div class="highlight-python notranslate"><div class="highlight"><pre>fig, axs = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(2, 1, figsize=(5, 3), tight_layout=True)

axs[0].plot(x1, y1)

axs[1].plot(x1, y1)

axs[1].xaxis.set_ticks(<a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.arange.html#numpy.arange" title="View documentation for numpy.arange">np.arange</a>(0., 8.1, 2.))

</pre></div>

</div>

We can of course fix this after the fact, but it does highlight a

weakness of hard-coding the ticks. This example also changes the format

of the ticks:

<div class="highlight-python notranslate"><div class="highlight"><pre>fig, axs = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(2, 1, figsize=(5, 3), tight_layout=True)

ticks = <a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.arange.html#numpy.arange" title="View documentation for numpy.arange">np.arange</a>(0., 8.1, 2.)

# list comprehension to get all tick labels...

tickla = ['%1.2f' % tick for tick in ticks]

axs[1].set_xlim(axs[0].get_xlim())

</pre></div>

</div>

</div>

<h3>Tick Locators and Formatters<a class="headerlink" href="#tick-locators-and-formatters" title="Permalink to this headline">¶</a></h3>

Instead of making a list of all the tickalbels, we could have

used a <a class="reference internal" href="../../api/ticker_api.html#matplotlib.ticker.FormatStrFormatter" title="matplotlib.ticker.FormatStrFormatter"><code class="xref py py-obj docutils literal notranslate">matplotlib.ticker.FormatStrFormatter</code></a> and passed it to the

<code class="docutils literal notranslate">ax.xaxis</code>

<div class="highlight-python notranslate"><div class="highlight"><pre>fig, axs = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(2, 1, figsize=(5, 3), tight_layout=True)

# list comprehension to get all tick labels...

formatter = <a href="../../api/ticker_api.html#matplotlib.ticker.StrMethodFormatter" title="View documentation for matplotlib.ticker.StrMethodFormatter">matplotlib.ticker.StrMethodFormatter</a>('{x:1.1f}')

axs[1].xaxis.set_major_formatter(formatter)

</pre></div>

</div>

And of course we could have used a non-default locator to set the

tick locations. Note we still pass in the tick values, but the

x-limit fix used above is not needed.

<div class="highlight-python notranslate"><div class="highlight"><pre>fig, axs = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(2, 1, figsize=(5, 3), tight_layout=True)

formatter = <a href="../../api/ticker_api.html#matplotlib.ticker.FormatStrFormatter" title="View documentation for matplotlib.ticker.FormatStrFormatter">matplotlib.ticker.FormatStrFormatter</a>('%1.1f')

locator = <a href="../../api/ticker_api.html#matplotlib.ticker.FixedLocator" title="View documentation for matplotlib.ticker.FixedLocator">matplotlib.ticker.FixedLocator</a>(ticks)

axs[1].xaxis.set_major_locator(locator)

axs[1].xaxis.set_major_formatter(formatter)

</pre></div>

</div>

The default formatter is the <a class="reference internal" href="../../api/ticker_api.html#matplotlib.ticker.MaxNLocator" title="matplotlib.ticker.MaxNLocator"><code class="xref py py-obj docutils literal notranslate">matplotlib.ticker.MaxNLocator</code></a> called as

<code class="docutils literal notranslate">ticker.MaxNLocator(self, nbins='auto', steps=[1, 2, 2.5, 5, 10])</code>

The steps keyword contains a list of multiples that can be used for

tick values. i.e. in this case, 2, 4, 6 would be acceptable ticks,

as would 20, 40, 60 or 0.2, 0.4, 0.6. However, 3, 6, 9 would not be

acceptable because 3 doesn’t appear in the list of steps.

<code class="docutils literal notranslate">nbins=auto</code> uses an algorithm to determine how many ticks will

be acceptable based on how long the axis is. The fontsize of the

ticklabel is taken into account, but the length of the tick string

is not (because its not yet known.) In the bottom row, the

ticklabels are quite large, so we set <code class="docutils literal notranslate">nbins=4</code> to make the

labels fit in the right-hand plot.

<div class="highlight-python notranslate"><div class="highlight"><pre>fig, axs = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(2, 2, figsize=(8, 5), tight_layout=True)

axs = axs.flatten()

for n, ax in enumerate(axs):

ax.plot(x1*10., y1)

locator = <a href="../../api/ticker_api.html#matplotlib.ticker.MaxNLocator" title="View documentation for matplotlib.ticker.MaxNLocator">matplotlib.ticker.MaxNLocator</a>(nbins='auto', steps=[1, 4, 10])

axs[1].xaxis.set_major_locator(locator)

axs[1].xaxis.set_major_formatter(formatter)

formatter = <a href="../../api/ticker_api.html#matplotlib.ticker.FormatStrFormatter" title="View documentation for matplotlib.ticker.FormatStrFormatter">matplotlib.ticker.FormatStrFormatter</a>('%1.5f')

locator = <a href="../../api/ticker_api.html#matplotlib.ticker.AutoLocator" title="View documentation for matplotlib.ticker.AutoLocator">matplotlib.ticker.AutoLocator</a>()

axs[2].xaxis.set_major_formatter(formatter)

axs[2].xaxis.set_major_locator(locator)

formatter = <a href="../../api/ticker_api.html#matplotlib.ticker.FormatStrFormatter" title="View documentation for matplotlib.ticker.FormatStrFormatter">matplotlib.ticker.FormatStrFormatter</a>('%1.5f')

axs[3].xaxis.set_major_formatter(formatter)

axs[3].xaxis.set_major_locator(locator)

</pre></div>

</div>

Finally, we can specify functions for the formatter using

<a class="reference internal" href="../../api/ticker_api.html#matplotlib.ticker.FuncFormatter" title="matplotlib.ticker.FuncFormatter"><code class="xref py py-obj docutils literal notranslate">matplotlib.ticker.FuncFormatter</code></a>.

<div class="highlight-python notranslate"><div class="highlight"><pre>def formatoddticks(x, pos):

"""Format odd tick positions

"""

if x % 2:

return '%1.2f' % x

else:

return ''

ax.plot(x1, y1)

formatter = <a href="../../api/ticker_api.html#matplotlib.ticker.FuncFormatter" title="View documentation for matplotlib.ticker.FuncFormatter">matplotlib.ticker.FuncFormatter</a>(formatoddticks)

ax.xaxis.set_major_formatter(formatter)

ax.xaxis.set_major_locator(locator)

</pre></div>

</div>

</div>

<h3>Dateticks<a class="headerlink" href="#dateticks" title="Permalink to this headline">¶</a></h3>

Matplotlib can accept <a class="reference external" href="https://docs.python.org/3/library/datetime.html#datetime.datetime" title="(in Python v3.7)"><code class="xref py py-obj docutils literal notranslate">datetime.datetime</code></a> and <code class="xref py py-obj docutils literal notranslate">numpy.datetime64</code>

objects as plotting arguments. Dates and times require special

formatting, which can often benefit from manual intervention. In

order to help, dates have spectial Locators and Formatters,

defined in the <a class="reference internal" href="../../api/dates_api.html#module-matplotlib.dates" title="matplotlib.dates"><code class="xref py py-obj docutils literal notranslate">matplotlib.dates</code></a> module.

A simple example is as follows. Note how we have to rotate the

tick labels so that they don’t over-run each other.

<div class="highlight-python notranslate"><div class="highlight"><pre>import datetime

base = datetime.datetime(2017, 1, 1, 0, 0, 1)

time = [base + datetime.timedelta(days=x) for x in range(len(y1))]

ax.plot(time, y1)

ax.tick_params(axis='x', rotation=70)

</pre></div>

</div>

Maybe the format of the labels above is acceptable, but the choices is

rather idiosyncratic. We can make the ticks fall on the start of the month

by modifying <a class="reference internal" href="../../api/dates_api.html#matplotlib.dates.AutoDateLocator" title="matplotlib.dates.AutoDateLocator"><code class="xref py py-obj docutils literal notranslate">matplotlib.dates.AutoDateLocator</code></a>

<div class="highlight-python notranslate"><div class="highlight"><pre>import matplotlib.dates as mdates

locator = <a href="../../api/dates_api.html#matplotlib.dates.AutoDateLocator" title="View documentation for matplotlib.dates.AutoDateLocator">mdates.AutoDateLocator</a>(interval_multiples=True)

</pre></div>

</div>

However, this changes the tick labels. The easiest fix is to pass a format

to <a class="reference internal" href="../../api/dates_api.html#matplotlib.dates.DateFormatter" title="matplotlib.dates.DateFormatter"><code class="xref py py-obj docutils literal notranslate">matplotlib.dates.DateFormatter</code></a>. Also note that the 29th and the

next month are very close together. We can fix this by using the

<code class="xref py py-obj docutils literal notranslate">dates.DayLocator</code> class, which allows us to specify a list of days of the

month to use. Similar formatters are listed in the <a class="reference internal" href="../../api/dates_api.html#module-matplotlib.dates" title="matplotlib.dates"><code class="xref py py-obj docutils literal notranslate">matplotlib.dates</code></a> module.

<div class="highlight-python notranslate"><div class="highlight"><pre>locator = <a href="../../api/dates_api.html#matplotlib.dates.DayLocator" title="View documentation for matplotlib.dates.DayLocator">mdates.DayLocator</a>(bymonthday=[1, 15])

formatter = <a href="../../api/dates_api.html#matplotlib.dates.DateFormatter" title="View documentation for matplotlib.dates.DateFormatter">mdates.DateFormatter</a>('%b %d')

</pre></div>

</div>

</div>

<h2>Legends and Annotations<a class="headerlink" href="#legends-and-annotations" title="Permalink to this headline">¶</a></h2>

<li>Legends: <a class="reference internal" href="../intermediate/legend_guide.html">Legend guide</a></li>

<li>Annotations: <a class="reference internal" href="annotations.html">Annotations</a></li>

</ul>

</div></blockquote>

<a class="reference download internal" href="../../_downloads/text_intro.py" download=""><code class="xref download docutils literal notranslate">Download Python source code: text_intro.py</code></a></div>

<a class="reference download internal" href="../../_downloads/text_intro.ipynb" download=""><code class="xref download docutils literal notranslate">Download Jupyter notebook: text_intro.ipynb</code></a></div>

</div>

Keywords: matplotlib code example, codex, python plot, pyplot

<a class="reference external" href="https://sphinx-gallery.readthedocs.io">Gallery generated by Sphinx-Gallery</a>

</div>

</div>

Last updated on Jun 28, 2018.

Created using

<ahref="http://sphinx-doc.org/">Sphinx</a> 1.7.5.

Doc version v2.2.2-101-g15e1eadd0.

</div>

</body>

</footer>

</html>

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

FilesExpand file tree

text_intro.html

Latest commit

History

text_intro.html

File metadata and controls