The shittiest dataframe method.
There's (at least) two common ways to filter a dataframe by rows that have a certain value in a column.
a = df.query('name == "myname"') b = df[df['name'] == 'myname']
pandas.DataFrame.query is really bizarre (https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.query.html). It takes a string as a parameter and that string is evaluated with pandas.eval(). The string can use @ to refer to variables.
It's still better than the second method. You can nicely chain the query method, which can't really be said for the second method.
(df .query('name == "myname"') .groupby('city') .sum() .reset_index() .head())