Open
Description
Hi Plotly team,
I'm encountering an issue when trying to display the sign for all Y-axis tick labels using the tickformat='+' format. Specifically, when the Y-axis includes a tick near zero, Plotly displays it in scientific notation instead of as +.
Problem
Setting tickformat='+' on the Y-axis leads to unexpected tick labels like -8.881784197e-17, which appears instead of a clean +0. This seems to be due to floating-point precision errors, but it's surprising that it breaks the format hint and drops into scientific notation.
Minimal reproducible example
import plotly.graph_objects as go
figure = go.Figure()
figure.add_scatter(
x=[1],
y=[0.58],
)
figure.update_layout(
yaxis={
'range': [-0.66, 0.66],
'tickformat': '+',
},
)
figure.show()

Expected Behavior
All tick labels on the Y-axis should respect the + format and include a sign, including zero. The tick at (or near) zero should be displayed as +0, not in scientific notation.
Thanks for the awesome work on Plotly!