我无法使用 matplotlib 在图表上标记数据点

Question

This is the code that I have been writing, but unable to add labels to the data points. Have tried multiple ways but getting error one after the other!! The data set in 9th line: 'country' is to be used as labelling. I want to label the 1st and last data point. Please Help!

```python
import pandas as pd
import numpy as np
from sklearn.cluster import KMeans
import matplotlib.pyplot as plt

data = pd.read_csv('happy_income1.csv')
happy = data['happyScore']
satis = data['avg_satisfaction']
country = data['country']

# Zapping 2 arrays together
satis_happy = np.column_stack((satis,happy))

# Sorting
data.sort_values('avg_satisfaction', inplace=True) #Sorting Data Column

# Filtering
satisfied = data[data['avg_satisfaction']>4] #Making Section as per requirement
print(satisfied)

# Making clusters as required
k_res = KMeans(n_clusters=3).fit(satis_happy)
cluster = k_res.cluster_centers_
print(cluster)

# Plotting
fig, week4 = plt.subplots()
week4.scatter(x=happy, y=satis)
week4.scatter(x=cluster[:,0], y=cluster[:,1], s=9999, alpha=0.25)
week4.set_xlabel('Happiness')
week4.set_ylabel('Satisfaction')
week4.set_title('Happiness versus Satisfaction')

# Labelling
# ----------------------------------------------

plt.show()
```

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Answer 1

You can add these two additional lines after plotting the scatter plots. They will add the text to the first and last entries. You can do additional things like background box, etc. if required. You can check matplotlib documentation and examples here

offset=0.05
week4.annotate(country[0], (happy[0]+offset, satis[0]+offset), color='red', weight='bold')
week4.annotate(country.iat[-1], (happy.iat[-1]+offset, satis.iat[-1]+offset), color='blue', weight='bold')

Output graph