5.2 图表绘制 : 作图模块化及模板：以柱状图为例
2018-07-26 本文已影响20人
数据成长之路
# -*- coding:utf-8 -*-
import numpy as np
from IPython.display import Image
import matplotlib.pyplot as plt
import matplotlib as mpl
import matplotlib.font_manager as mfm
import matplotlib.gridspec as gridspec
import matplotlib.ticker as plticker
目标图表形式
Image('./source/plot_bar.png')
data = np.array([['$0-$5', 8],
['$5-$10', 28],
['$10-$15', 22],
['$15-$20', 15],
['$20-$25', 9],
['$25-$30', 13],
['$30-$35', 12],
['$35-$40', 2],
['$40-$45', 3],
['$50以上', 11]], dtype=object)
data[:,1]
array([8, 28, 22, 15, 9, 13, 12, 2, 3, 11], dtype=object)
前期准备
准备需要的字体handle
要想在图表中显示中文，需要使用中文字体，而matplotlib中提供了直接使用自定义字体的handle，我们只需要预设好想要使用的字体。
# 把字体文件放入font文件夹中，也可以在此设置字体文件的路径
font_path = {'hei':'./font/MSYHMONO.ttf',
'english' : './font/Calibri.ttf'}
# 实例化可以直接使用的字体handle
prop = {font_name : mfm.FontProperties(fname=font_path[font_name])
for font_name in list(font_path)}
# 设置可选配色
default_colors = {}
default_colors['blue'] = '#6CADDD'
default_colors['yellow'] = '#F3903F'
default_colors['red'] = '#CB615A'
default_colors['orange'] = '#F3903F'
default_colors['gray'] = '#B4B4B4'
default_colors['lightyellow'] = '#FCC900'
default_colors['royalblue'] = '#5488CF'
做出初始的图布
length = len(data)
x = np.arange(length)
y = data[:,1]
# 首先设置作图的大小
IMAGE_WIDTH = 5.708
IMAGE_HIGH = 2.756
# 实例化Figure
fig = plt.figure(figsize=(IMAGE_WIDTH, IMAGE_HIGH))
# 添加gs，方便后续的设置
gs = gridspec.GridSpec(1, 1)
# 在gs上添加作图用的Axes
ax = fig.add_subplot(gs[0])
fig
设置横坐标标签
# 字体为黑体9号
xticks_font = prop['hei'].copy()
xticks_font.set_size(9)
# 文字的倾斜角度为水平
xticks_rotation = 'horizontal'
labels = data[:,0]
plt.xticks(x, labels, fontproperties=xticks_font, rotation=xticks_rotation)
fig
labels
array(['$0-$5', '$5-$10', '$10-$15', '$15-$20', '$20-$25', '$25-$30',
'$30-$35', '$35-$40', '$40-$45', '$50以上'], dtype=object)
注意
labels中的结果使用'$0-$5'的形式无法正常显示$，需要在$前加入\
labels = list(map(lambda x:x.replace('$', '\$'), data[:,0]))
plt.xticks(x, labels, fontproperties=xticks_font, rotation=xticks_rotation)
fig
画出基本图形
rects = plt.bar(x, y, 0.4, zorder=3, color=default_colors['blue'])
fig
添加标注
for rect in rects:
height = rect.get_height()
ax.text(rect.get_x() + rect.get_width()/2., 1.05*height,
'%d' % int(height),
ha='center', va='bottom')
fig
调整边框Spines
ax.spines['right'].set_visible(False)
ax.spines['top'].set_visible(False)
ax.spines['left'].set_visible(False)
fig
去除多余的Tick
ax.tick_params(axis='both', which='both', bottom=False, top=False,
labelbottom=True, left=False, right=False, labelleft=True)
fig
添加标题
# 设置标题为黑体，14号
title_font = prop['hei'].copy()
title_font.set_size(14)
# 设置标题内容
title = "榜单商品价格分布"
# 设置标题相对图片的位置
title_y = 1.2
ax.set_title(title, fontproperties=title_font, y=title_y)
fig
添加图例
# 设置图例格式
legend_font = prop['hei'].copy()
legend_font.set_size(9)
# 图例内容
legend_name=['商品数量']
ax.legend(legend_name, loc='upper right', bbox_to_anchor=(1, 1.2), prop=legend_font, frameon=True)
fig
紧凑排布
现在虽然内容已经添加设置完毕，但是排布太过稀松，需要使用较为紧密的排布
gs.tight_layout(fig)
fig
添加Grid
使用快速grid可以添加方格状的grid，但是我们需要的是对y轴进行5-6次分割的grid，所以我们可以手动设置分割间隔。
ax.grid()
fig
使用快速grid可以添加方格状的grid，但是我们需要的是对y轴进行5-6次分割的grid，所以我们可以手动设置分割间隔。
intervals = 5
loc = plticker.MultipleLocator(base=intervals)
ax.yaxis.set_major_locator(loc)
ax.grid(axis='y', zorder=0)
fig
不过每一次都手动设定y轴间隔太过麻烦了，所以我们可以手动写个自动划分的函数，确定间隔
# 获取y轴取值范围
get_ax_space = lambda x: x.get_ylim()[1] - x.get_ylim()[0]
ax_space = get_ax_space(ax)
print("y轴取值范围 : {}".format(ax_space))
def get_interval(ax_space, space_number=5):
digit_number = len(str((ax_space)))
intervals = int((ax_space)/(space_number*(10**digit_number)))
while intervals == 0:
digit_number -= 1
intervals = int((ax_space)/(space_number*(10**digit_number)))
linshi = round((ax_space)/(space_number*(10**digit_number)))
intervals = linshi*(10**digit_number)
return intervals
intervals = get_interval(ax_space)
print("y轴grid间隔为 ：{}".format(intervals))
loc = plticker.MultipleLocator(base=intervals)
ax.yaxis.set_major_locator(loc)
ax.grid(axis='y', zorder=0)
fig
y轴取值范围 : 29.4
y轴grid间隔为 ：6.0
模块化： 整理为可复用的模板（作业）
模块化结果
# -*- coding: utf-8 -*-
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
import matplotlib.font_manager as mfm
import matplotlib.gridspec as gridspec
import matplotlib.ticker as plticker
class Image(object):
font_path = {}
prop = {}
font_path['hei'] = './font/MSYHMONO.ttf'
font_path['english'] = './font/Calibri.ttf'
for font_name in list(font_path):
prop[font_name] = mfm.FontProperties(fname=font_path[font_name])
title_font = prop['hei'].copy()
title_font.set_size(14)
xticks_font = prop['hei'].copy()
xticks_font.set_size(9)
ylable_font = prop['hei'].copy()
ylable_font.set_size(10)
legend_font = prop['hei'].copy()
legend_font.set_size(9)
default_colors = {}
default_colors['blue'] = '#6CADDD'
default_colors['yellow'] = '#F3903F'
default_colors['red'] = '#CB615A'
default_colors['orange'] = '#F3903F'
default_colors['gray'] = '#B4B4B4'
default_colors['lightyellow'] = '#FCC900'
default_colors['royalblue'] = '#5488CF'
IMAGE_WIDTH = 5.708
IMAGE_HIGH = 2.756
def __init__(self, title=None, labels=None, data=None,
image_path=None, title_y=1.1, xticks_rotation='vertical', legend_name=[]):
self.length = len(data)
self.x = np.arange(self.length)
self.y = data
self.data = data
self.title_y = title_y
self.title = title
self.labels = labels
self.legend_name = legend_name
self.xticks_rotation = xticks_rotation
def init(self):
self.fig = plt.figure(figsize=(self.IMAGE_WIDTH, self.IMAGE_HIGH))
self.gs = gridspec.GridSpec(1, 1)
self.ax = self.fig.add_subplot(self.gs[0])
self.set_xticks()
self.add_title()
self.plot()
self.set_spines()
self.set_tick_marks()
self.add_legend()
# 补充设定
self.config_add()
self.tight_layout()
self.set_grid()
plt.close()
def add_legend(self):
if not (self.legend_name is None):
self.ax.legend(self.legend_name, loc='upper right', bbox_to_anchor=(1, 1.2), prop=self.legend_font, frameon=True)
def tight_layout(self, **karg):
self.gs.tight_layout(self.fig, **karg)
def plot(self):
rects = plt.bar(self.x, self.y, 0.4, zorder=3, color=self.default_colors['blue'])
for rect in rects:
height = rect.get_height()
self.ax.text(rect.get_x() + rect.get_width()/2., 1.05*height,
'%d' % int(height),
ha='center', va='bottom')
def add_title(self):
if self.title:
self.ax.set_title(self.title, fontproperties=self.title_font, y=self.title_y)
def set_grid(self):
get_ax_space = lambda x: x.get_ylim()[1] - x.get_ylim()[0]
self.ax_space = get_ax_space(self.ax)
def get_interval(ax_space, space_number=5):
digit_number = len(str((ax_space)))
intervals = int((ax_space)/(space_number*(10**digit_number)))
while intervals == 0:
digit_number -= 1
intervals = int((ax_space)/(space_number*(10**digit_number)))
linshi = round((ax_space)/(space_number*(10**digit_number)))
intervals = linshi*(10**digit_number)
return intervals
if not 'intervals' in self.__dict__.keys():
self.intervals = get_interval(self.ax_space)
loc = plticker.MultipleLocator(base=self.intervals)
self.ax.yaxis.set_major_locator(loc)
self.ax.grid(axis='y', zorder=0)
if 'ax2' in self.__dict__.keys():
print("有双轴需要设置副轴grid")
self.ax_space2 = get_ax_space(self.ax2)
self.intervals2 = get_interval(self.ax_space2, space_number=5)
loc2 = plticker.MultipleLocator(base=self.intervals2)
self.ax2.yaxis.set_major_locator(loc2)
def set_spines(self):
self.ax.spines['right'].set_visible(False)
self.ax.spines['top'].set_visible(False)
self.ax.spines['left'].set_visible(False)
def set_tick_marks(self):
self.ax.tick_params(axis='both', which='both', bottom=False, top=False,
labelbottom=True, left=False, right=False, labelleft=True)
def set_xticks(self):
plt.xticks(self.x, self.labels, fontproperties=self.xticks_font, rotation=self.xticks_rotation) # 设置横坐标标签
def show(self):
plt.show()
def save(self):
if image_path:
self.fig.savefig(image_path)
else:
logging.warning("Please sure image path firse")
def config_add(self):
"""
保留用于扩展功能或者设定
"""
pass
image = Image(data=data[:,1],
labels=list(map(lambda x:x.replace('$', '\$'), data[:,0])),
title='榜单商品价格分布',
xticks_rotation=0,
legend_name=['商品数量']
)
image.init()
image.fig
