Python pandas 线图：将 x 轴更改为线性

Question

I have a pandas dataframe which looks like:

df.x = [2, 4, 16, 256]

df.y = [1,2,4,16]

I would like to do a line plot with linear x-axis, although the x values are not linear.

Currently if I plot this dataframe as df.plot(), I get this because the x values are not linear:

But, the above graph does not show the trend correctly. I want this:

Note that the X-axis ticks and labels are linear, though the values are not.

How can I plot the graph correctly? I tried renaming the xticklabels but it did not work.

Answer 1

Your index ( X axis) seems to be of object (string) dtype) - convert it to numeric dtype before plotting.

Demo:

In [99]: df.index.dtype
Out[99]: dtype('O')   # <----- NOTE !

plotting original DF:

In [100]: df.plot()
Out[100]: <matplotlib.axes._subplots.AxesSubplot at 0xe74e278>

let's convert index to numeric dtype and plot it again:

In [101]: df.set_index(pd.to_numeric(df.index, errors='coerce')).plot()
Out[101]: <matplotlib.axes._subplots.AxesSubplot at 0xadd94e0>

Answer 2

You need to set_index

df.set_index('x').y.plot()