如何 plot 分散 plot 以获取范围数据

Question

I'm having range data for example an educational institute is charging fee for batch of students for online courses.

If 1-4 students join the fee is 10000/per batch

If 5-10 students join the fee is 15000/per batch

If 11-20 students join the fee is 22000/per batch

x = ['1-4','5-10','11-20']
y = [10000,15000,20000]

The x and y is my xlable and ylable for matplotlib. In this case how to transform the data of x and plot as xlable.

Answer 1

The x and y arrays can be converted into arrays of numeric values that can be used to create a scatter plot:

1. convert the x string into ranges

x_ranges = [list(range(int(xi[0]), int(xi[1])+1)) for xi in [xi.split('-') for xi in x]]
#[[1, 2, 3, 4], [5, 6, 7, 8, 9, 10], [11, 12, 13, 14, 15, 16, 17, 18, 19, 20]]

2. add one y element per entry in the corresponding x range

y_expanded = [(x[0], [x[1]]*len(x[0])) for x in zip(x_ranges,y)]
#[([1, 2, 3, 4], [10000, 10000, 10000, 10000]),
# ([5, 6, 7, 8, 9, 10], [15000, 15000, 15000, 15000, 15000, 15000]),
# ([11, 12, 13, 14, 15, 16, 17, 18, 19, 20],
#  [20000, 20000, 20000, 20000, 20000, 20000, 20000, 20000, 20000, 20000])]

3. re-group the x and y arrays

xy_sorted = list(map(list, zip(*y_expanded)))
#[[[1, 2, 3, 4], [5, 6, 7, 8, 9, 10], [11, 12, 13, 14, 15, 16, 17, 18, 19, 20]],
# [[10000, 10000, 10000, 10000],
#  [15000, 15000, 15000, 15000, 15000, 15000],
#  [20000, 20000, 20000, 20000, 20000, 20000, 20000, 20000, 20000, 20000]]]

4. flatten the list for the x and y values

x_result = [x for sublist in xy_sorted[0] for x in sublist]
#[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
y_result = [y for sublist in xy_sorted[1] for y in sublist]
#[10000, 10000, 10000, 10000, 15000, 15000, ...]

5. create the scatter plot

plt.xticks(x_result)
plt.ylim(0, max(y_result)+1000)
plt.scatter(x_result, y_result)
plt.show()