Is it possible to put the `plt.yticks` between the horizontal bars?

问题

I'm trying to put the value in the plt.yticks between the bars. Unfortunately, I have no idea how to do it. Is it possible?, if it is can anyone give some tips?

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

age = np.array(
    ["0 - 4", "5 - 9", "10 - 14", "15 - 19", "20 - 24", "25 - 29", "30 - 34", "35 - 39",
     "40 - 44", "45 - 49", "50 - 54", "55 - 59", "60 - 64", "65 - 69", "70 - 74",
     "75 - 79", "80 - 84", "85 - 89", "90 - 94", "95 - 99", "> 100"])
m = np.array(
    [1915887, 2100931, 2494484, 2464805, 2361297, 2529633, 2669927, 2754129, 2753282,
     2552531, 2211649, 1697221, 1311024, 902675, 722246, 482686, 273915, 108639, 35867,
     10965, 1238])
f = np.array(
    [1823981, 1980712, 2369795, 2435784, 2330223, 2562964, 2724990, 2860720, 2918730,
     2713534, 2376384, 1869867, 1454373, 1030677, 885393, 640698, 388748, 172302, 64170,
     19868, 2711])
x = np.arange(age.size)
tick_lab = ['3M', '2M', '1M', '1M', '2M', '3M']
tick_val = [-3000000, -2000000, -1000000, 1000000, 2000000, 3000000]


def plot_pyramid():
    plt.barh(x, -m, alpha=.75, height=.75, align='center' , color="deepskyblue")
    plt.barh(x, f, alpha=.75, height=.75, align='center', color="pink")
    plt.yticks(x, age)
    plt.xticks(tick_val, tick_lab)
    plt.grid(b=False)
    plt.title("Population Pyramid")
    plt.show()


if __name__ == '__main__':
    plot_pyramid()

Chart generated by this code

回答1:

I just replaced the two plt.barh lines by the below lines and added the for loop after plt.title inside the function and replaced ax.set_yticks(False) by plt.yticks([]). I am not sure if this is exactly what you want.

# Modified before the function because you are shifting the bars left/right
tick_val = np.array([-3000000, -2000000, -1000000, 1000000, 2000000, 3000000])
shift = 300000
tick_val[0:3] -= shift
tick_val[3:] += shift

# Modified inside the function
plt.barh(x, -m, alpha=.75, height=.75, left=-shift, align='center' , color="deepskyblue")
plt.barh(x, f, alpha=.75, height=.75, left = shift, align='center', color="pink")

for i, j in enumerate(age):
    if i==0 or i==1:
        plt.text(-150000, x[i]-0.2, j, fontsize=10)
    else:    
        plt.text(-230000, x[i]-0.2, j, fontsize=10)

Output

来源：https://stackoverflow.com/questions/52012462/is-it-possible-to-put-the-plt-yticks-between-the-horizontal-bars