Matplotlib set axis scale interval

I wanted the horizontal axis to show 1-20 The integer of , Interval between scales 1, But the plot shows floating point numbers

plt.title('train loss')
plt.plot(np.arange(1,len(losses)+1), losses)
plt.plot(np.arange(1,len(eval_losses)+1), eval_losses)

After checking the data , Find two ways ：
The first is through MultipleLocator Class to achieve

from matplotlib.pyplot import MultipleLocator # Import this class , Set the axis spacing 
plt.title('train loss')

x_major_locator=MultipleLocator(1)
ax=plt.gca()
ax.xaxis.set_major_locator(x_major_locator)

plt.plot(np.arange(1,len(losses)+1), losses)
plt.plot(np.arange(1,len(eval_losses)+1), eval_losses)

The second is to convert the horizontal axis coordinate range into a string

plt.title('train loss')
plt.plot(np.arange(1,len(losses)+1).astype(np.str), losses)
plt.plot(np.arange(1,len(eval_losses)+1), eval_losses)