How do you plot a trendline for a dataset imported from Excel?-CodePudding

I have been trying to plot a trendline for a data set of 161 mean temperature values which I imported from Excel with the help of pandas. But I can't manage to create a trendline for the data set. I've followed tutorials on YouTube and other sites, but it doesn't work. I do not get a trend line no matter what I do. I've tried something like this:

m, b = polyfit(data.Year, data.January, 1)
fit = m*(data.Year)   b
plt.plot(data.Year, fit)

This method doesn't do anything. I'd love some help to fix this problem, thank you.

CodePudding user response：

An alternate method using the newer

CodePudding user response：

If you're using matplotlib, you can use polyfit to generate a trendline: import matplotlib.pyplot as plt import numpy as np


# create sample data
xdata = np.array([0,1,2,3,4,5,6,7,8,9])
ydata = np.array([0,1,2,2.5,3.5,4,5,5.5,6,7])

# calculate polynomial
z = np.polyfit(xdata, ydata, 1)
f = np.poly1d(z)

# calculate new x's and y's
x_new = np.linspace(xdata[0], xdata[-1], 50)
y_new = f(x_new)

plt.plot(xdata, ydata, 'o', x_new, y_new)
plt.xlim([xdata[0]-1, xdata[-1]   1])
plt.show()