Cactus Philosopher questions

• Count the frequency of characters at a position in a string in a Pandas DataFrame column
• Groupby and select the first, second, and fourth member of each group?
• Lower triangle mask with seaborn clustermap
• Groupby and assign unique IDs to group members
• Matplotlib - selecting colors within qualitative color map
• Drop all rows in Pandas DataFrame where value is NOT NaN

Cactus Philosopher answers