Seaborn Color Palette not working appropiate with lineplot

Question

I'm having a little trouble with customizing my colors for a lineplot. I want to show an ensemble of spectras with a sequential color palette. The argument "palette="blues" works fine, but does not accept any appropriate color lists (like "Blues_d"), which do not include any bright colors.

Below you can see the code I'm using.

color = (sns.dark_palette("purple"))
sns.set()

ax = sns.lineplot(x="Wavelength", y="Absorption", hue="t (min)", lw=1, data=df1, palette=color, legend="brief")

The problem is, that I get the following error:

ValueError: The palette list has the wrong number of colors.

So the question is: How can I use the lineplot function and using a sequential color palette of blues, reds, or whatever that do not include any bright colors?

I'm using pandas version 0.23.3, matplotlib version 2.2.2 and seaborn version 0.9.0

Answer 1

Since you mention the t (min) column in the hue option, you need to know the total number of unique values of the column.

Assume that there are 5 unique values in the column. You, thus, can set the number to the n_colors option of sns.color_palette:

ax = sns.lineplot(x="Wavelength", 
                  y="Absorption", 
                  hue="t (min)", 
                  lw=1, 
                  data=df1, 
                  palette=sns.color_palette('coolwarm', n_colors=5), 
                  legend="brief")

Answer 2

No need to worry about the color count if you set your color palette as a color map by setting "as_cmap" argument to True in sns.color_palette:

ax = sns.lineplot(x="Wavelength", 
                      y="Absorption", 
                      hue="t (min)", 
                      lw=1, 
                      data=df1, 
                      palette=sns.color_palette('coolwarm', as_cmap = True), 
                      legend="brief")