# Dash Subplot TypeError: 'Patch' object is not callable

**URL:** <https://community.plotly.com/t/dash-subplot-typeerror-patch-object-is-not-callable/84349>\
**Category:** Dash Python\
**Tags:** question\
**Created:** [May 7, 2024, 9:04pm UTC](https://community.plotly.com/t/dash-subplot-typeerror-patch-object-is-not-callable/84349 "2024-05-07T21:04:55Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![GaNick](https://avatars.discourse-cdn.com/v4/letter/g/f05b48/32.png) [@GaNick](https://community.plotly.com/u/GaNick)\
**Post date:** [May 7, 2024, 9:04pm UTC](https://community.plotly.com/t/dash-subplot-typeerror-patch-object-is-not-callable/84349/1 "2024-05-07T21:04:55Z")

</div>

Hello, New to Dash. I’m trying to Patch a subplot to do things like adding an extra trace somewhere and such. It gives me this error when I use the `add_trace()` function to the `patched_figure = Patch()`.

This is my code.

```auto
app = Dash( __name__ )
subplot = subplots.make_subplots(figure=None) # Define Subplot

app.layout = html.Div([
        html.Button("Update Sublot", id="update-trace"),
        dcc.Graph(figure=subplot, id="my-fig"),
])

@callback(Output("my-fig", "figure"), Input("update-trace", "n_clicks"))
def my_callback(n_clicks):
    # Defining a new random trace
    v = np.arange(-3, 5.1, 0.1) # x-axis
    i = []
    for each in v:
        i.append(1e-3*(2*random.random() - 1)) # y-axis

    # Creating a Patch object
    patched_figure = Patch()
    patched_figure.add_trace(go.Scatter(x=v, y=i, mode="lines"),
                row=(1), col=(1)) # Adds trace at column and row
    return patched_figure

if __name__ == " __main__":
    app.run(debug=True)
        

```

Error:

> patched\_figure.add\_trace(go.Scatter(x=v, y=i, mode=“lines”),  
> TypeError: ‘Patch’ object is not callable

I’ve searched and can only seem to find solutions that involve `Patch()['data'].append(...)` but I think I also need the `row` and `col` parameters from `add_trace()` to choose as well. Any ideas?

---

<div class="post-metadata">

**Author:** ![AIMPED](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/aimped/32/21758_2.png) [@AIMPED](https://community.plotly.com/u/AIMPED)\
**Post date:** [May 15, 2024, 7:26pm UTC](https://community.plotly.com/t/dash-subplot-typeerror-patch-object-is-not-callable/84349/2 "2024-05-15T19:26:26Z")

</div>

Hi @GaNick welcome to the forums.

You are on the right track. If you ant to use the `Patch()` you need to stick to the methods of it. With `append` you can add a trace.

Does your plot really have only one trace? If this was the case, you could do this:

```python
import dash
from plotly.subplots import make_subplots
import plotly.graph_objects as go
from dash import Input, Output,Patch, callback, html, dcc
import numpy as np
import random

app = dash.Dash( __name__ )
subplot = make_subplots(figure=None) # Define Subplot

app.layout = html.Div([
        html.Button(
            "Update Sublot",
            id="update-trace"
        ),
        dcc.Graph(
            figure=subplot, 
            id="my-fig"
        ),
])

@callback(Output("my-fig", "figure"), Input("update-trace", "n_clicks"))
def my_callback(n_clicks):
    # Defining a new random trace
    v = np.arange(-3, 5.1, 0.1) # x-axis
    i = []
    for each in v:
        i.append(1e-3*(2*random.random() - 1)) # y-axis

    # Creating a Patch object
    patched_figure = Patch()
    patched_figure['data'].append(
        go.Scatter(x=v, y=i, mode="lines")
    )
    return patched_figure

if __name__ == " __main__":
    app.run(debug=True)

```

If you have “real” subplots, you can choose where to add the traces via the corresponding axis:

```python
import dash
from plotly.subplots import make_subplots
import plotly.graph_objects as go
from dash import Input, Output, Patch, callback, html, dcc, State
import numpy as np
import json

app = dash.Dash( __name__ )
fig = make_subplots(rows=1, cols=2)

fig.add_trace(
    go.Scatter(x=[1, 2, 3], y=[4, 5, 6]),
    row=1, col=1
)

fig.add_trace(
    go.Scatter(x=[10, 20, 30], y=[40, 50, 60]),
    row=1, col=2
)

app.layout = html.Div([
    html.Button(
        "Update Sublot",
        id="update-trace"
    ),
    dcc.Graph(
        figure=fig,
        id="my-fig"
    ),
])

@callback(
    Output("my-fig", "figure"),
    Input("update-trace", "n_clicks"),
    prevent_initial_call=True
)
def my_callback(_):
    # Defining a new random trace
    v = np.arange(4) # x-axis
    i = np.random.randint(4, 7, size=v.shape[0])

    # Creating a Patch object
    patched_figure = Patch()
    patched_figure['data'].extend(
        [
            go.Scatter(x=v*10, y=i*10, mode="lines", xaxis="x2", yaxis="y2"),
            go.Scatter(x=v, y=i, mode="lines")
        ]
    )
    return patched_figure

if __name__ == " __main__":
    app.run(debug=True)

```

In this example it helps paying attention to the x-axis range to distinguish between the subplots. I used `patch.extend()` just for demonstration, you could obviously use `append()` too.

![Peek 2024-05-15 21-50](https://us1.discourse-cdn.com/flex024/uploads/plot/original/3X/8/2/821cdbe916ba217a6769783efdec2c2092cc6fb3.gif)

mred patch subplots

---

<div class="post-metadata">

**Author:** ![GaNick](https://avatars.discourse-cdn.com/v4/letter/g/f05b48/32.png) [@GaNick](https://community.plotly.com/u/GaNick)\
**Post date:** [May 17, 2024, 10:41pm UTC](https://community.plotly.com/t/dash-subplot-typeerror-patch-object-is-not-callable/84349/3 "2024-05-17T22:41:25Z")

</div>

This will work!