# Changing the legend names on plotly express line chart

**URL:** <https://community.plotly.com/t/changing-the-legend-names-on-plotly-express-line-chart/60226>\
**Category:** 📊 Plotly Python\
**Created:** [January 19, 2022, 1:00pm UTC](https://community.plotly.com/t/changing-the-legend-names-on-plotly-express-line-chart/60226 "2022-01-19T13:00:03Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Nilesh21](https://avatars.discourse-cdn.com/v4/letter/n/54ee81/32.png) [@Nilesh21](https://community.plotly.com/u/Nilesh21)\
**Post date:** [January 19, 2022, 1:00pm UTC](https://community.plotly.com/t/changing-the-legend-names-on-plotly-express-line-chart/60226/1 "2022-01-19T13:00:03Z")

</div>

Hello Everyone,  
i am using numpy array [3,10] to plot the line chart using plotly express. The problem is i am not able to rename the legend names which are ‘wide\_variable\_0’ (default) and so on, The line plot variable is driven by dropdown menu. i have already tried the ‘label’ property but its not working.  
please find attached screenshot and demo code for referance .  
Any suggestion would be appreciated on how can i change the default legend names.  
Have a nice day ahead

 ![referance_image](https://us1.discourse-cdn.com/flex024/uploads/plot/original/3X/1/f/1f472355ee97c14ec753e0437b8948f2cfc004f1.jpeg)

import dash  
import numpy as np  
import dash\_html\_components as html  
import dash\_core\_components as dcc  
import plotly.graph\_objects as go  
import plotly.express as px

app = dash.Dash( **name** )

line\_plot = go.Figure()

app.layout = html.Div([  
html.H1(‘Line Plot’),

```
html.Div(
    dcc.Dropdown(
        id='page-1-dropdown',
        options=[{'label': i, 'value': i} for i in ['first','second','third']],
        value='first'
)),
html.Div(
dcc.Graph(id='line-plot',
          figure=line_plot))
])

```

@app.callback(dash.dependencies.Output(‘line-plot’, ‘figure’),  
[dash.dependencies.Input(‘page-1-dropdown’, ‘value’)])

def display\_page(value):  
“”“using numpy [3,10] matrix to plot the line plot in which ‘x axis’ will be the first list from the array and other two will be the ‘Y axis’ from matrix”""

```
data = [np.random.rand(3, 10) for _ in range(4)]
first_data = data[0]
second__data = data[1]
third_data = data[2]
if value == 'first':
    x_axis = [x for x in first_data[0]]
    y_axis = [y for y in first_data[1:]]
    fig = px.line(x=x_axis, y=y_axis)
    return fig
elif value == 'second' :
    x_axis = [x for x in second__data[0]]
    y_axis = [y for y in second__data[1:]]
    fig = px.line(x=x_axis, y=y_axis)
    return fig
elif value == 'third' :
    x_axis = [x for x in third_data[0]]
    y_axis = [y for y in third_data[1:]]
    fig = px.line(x=x_axis, y=y_axis)
    return fig

```

if **name** == ‘ **main** ’:  
app.run\_server(debug=True, port = 8090)

---

<div class="post-metadata">

**Author:** ![jlfsjunior](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/jlfsjunior/32/16061_2.png) [@jlfsjunior](https://community.plotly.com/u/jlfsjunior)\
**Post date:** [January 21, 2022, 10:52am UTC](https://community.plotly.com/t/changing-the-legend-names-on-plotly-express-line-chart/60226/2 "2022-01-21T10:52:05Z")

</div>

Hi,

You have a few options in my opinion, but to my knowledge you can’t just pass as a parameter to `px.line`…

1. Create a pandas dataframe from the array (with specific column names) and use it to make `fig`:

```auto
data = np.random.rand(3, 10) 
df = pd.DataFrame(data.transpose(), columns=["x", "y0", "y1"]) 
fig = px.line(df, x="x", y=["y0", "y1"])

```

1. Modify the trace name _after_`fig` is created:

```auto
x_axis = [x for x in first_data[0]]
y_axis = [y for y in first_data[1:]]
fig = px.line(x=x_axis, y=y_axis)

for idx, trace in enumerate(fig["data"]):
     trace["name"] = f"y{idx}" 

```

1. Use `plotly.graph_objects` and its constructors (a bigger change):

```auto
import plotly.graph_objects as go

data = np.random.rand(3, 10) 

x_axis = [x for x in data[0]]
y_axis = [y for y in data[1:]]
fig = go.Figure(
     [
        go.Scatter(x=x_axis, y=y, mode="lines", name=f"y{idx}") 
        for idx, y in enumerate(y_axis)
     ],
     layout={"showlegend": True}
)

```

Hope this helps!