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        "\n# Textbox\n\nThe Textbox widget lets users interactively provide text input, including\nformulas. In this example, the plot is updated using the `.on_submit` method.\nThis method triggers the execution of the *submit* function when the\nuser presses enter in the textbox or leaves the textbox.\n\nNote:  The `matplotlib.widgets.TextBox` widget is different from the following\nstatic elements: `annotations` and\n:doc:`/gallery/text_labels_and_annotations/placing_text_boxes`.\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
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      "source": [
        "import matplotlib.pyplot as plt\nimport numpy as np\n\nfrom matplotlib.widgets import TextBox\n\nfig, ax = plt.subplots()\nfig.subplots_adjust(bottom=0.2)\n\nt = np.arange(-2.0, 2.0, 0.001)\nl, = ax.plot(t, np.zeros_like(t), lw=2)\n\n\ndef submit(expression):\n    \"\"\"\n    Update the plotted function to the new math *expression*.\n\n    *expression* is a string using \"t\" as its independent variable, e.g.\n    \"t ** 3\".\n    \"\"\"\n    ydata = eval(expression, {'np': np}, {'t': t})\n    l.set_ydata(ydata)\n    ax.relim()\n    ax.autoscale_view()\n    plt.draw()\n\n\naxbox = fig.add_axes((0.1, 0.05, 0.8, 0.075))\ntext_box = TextBox(axbox, \"Evaluate\", textalignment=\"center\")\ntext_box.on_submit(submit)\ntext_box.set_val(\"t ** 2\")  # Trigger `submit` with the initial string.\n\nplt.show()"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        ".. admonition:: References\n\n   The use of the following functions, methods, classes and modules is shown\n   in this example:\n\n   - `matplotlib.widgets.TextBox`\n\n"
      ]
    }
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