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    import numpy as np
    import seaborn as sns
    import matplotlib.pyplot as plt
    import pandas as pd
    planets = pd.read_csv("planets.csv", sep=',')

    sns.set(style="ticks")
    # Initialize the figure with a logarithmic x axis
    f, ax = plt.subplots(figsize=(7, 6))
    ax.set_xscale("log")

    sns.swarmplot(x="pl_pnum", y="st_mass", data=planets,
                  size=2, color=".3", linewidth=0)
    # Tweak the visual presentation
    ax.xaxis.grid(True)
    ax.set(ylabel="")
    sns.despine(trim=True, left=True)

Error--------------------------------------------------------------------------------------------------------

Traceback (most recent call last):
  File "C:/Users/params4/Downloads/test.py", line 13, in <module>
    size=2, color=".3", linewidth=0)
  File "C:\Program Files (x86)\Python 35-32\lib\site-packages\seaborn\categorical.py", line 2786, in swarmplot
    dodge, orient, color, palette)
  File "C:\Program Files (x86)\Python 35-32\lib\site-packages\seaborn\categorical.py", line 1203, in __init__
    self.establish_variables(x, y, hue, data, orient, order, hue_order)
  File "C:\Program Files (x86)\Python 35-32\lib\site-packages\seaborn\categorical.py", line 151, in establish_variables
    raise ValueError(err)
ValueError: Could not interpret input 'pl_pnum'
>>>