A line chart or line graph is a type of chart which displays information as a series of data points called ‘markers’ connected by straight line segments. It is similar to a scatter plot except that the measurement points are ordered (typically by their xaxis value) and joined with straight line segments.
 Basic lineplot

This post describes how the plot function of matplotlib works. If you give only a serie of values, matplotlib will consider that these values are ordered and will use values from 1 to n to create the X axis (figure 1):
# libraries import matplotlib.pyplot as plt import numpy as np # create data values=np.cumsum(np.random.randn(1000,1)) # use the plot function plt.plot(values)
 Seaborn customization

For a more trendy look, just load the seaborn library. You will automatically get the look of figure 2.
# libraries import matplotlib.pyplot as plt import numpy as np import seaborn as sns # create data values=np.cumsum(np.random.randn(1000,1)) # use the plot function plt.plot(values)
 Use lineplot with ordered data !

Of course you can make a line chart from 2 series of values (X and Y axis). However, make sure that your X axis values are ordered! If not you will get this kind of figure (figure 3).
# libraries and data import matplotlib.pyplot as plt import numpy as np import seaborn as sns import pandas as pd df=pd.DataFrame({'xvalues': range(1,101), 'yvalues': np.random.randn(100) }) # plot plt.plot( 'xvalues', 'yvalues', data=df) plt.show()
 Use lineplot with ordered data !

If your X data are ordered, then you will get the same figure than figure 1:
# libraries import matplotlib.pyplot as plt import seaborn as sns # import the iris dataset df = sns.load_dataset('iris') # plot plt.plot( 'sepal_width', 'sepal_length', data=df) plt.show()