matplotlib的初次使用

初次尝试python的matplotlib，因为论文有一堆数据要处理，只能自学。就是所谓的用到什么学什么吧。

下面记录一下：首先统计所有阈值的频率，用dictionary来存储；参考官方网址对plt.bar()的各个参数解释，建立相应的柱状图。

代码如下：

# encoding:utf-8
import numpy as np
import math
from matplotlib import pyplot as plt

# 0的字典
dic0 = {}
# 1的字典
dic1 = {}

def autolabel(rects):
    for rect in rects:
        height = rect.get_height()
        plt.text(rect.get_x() + rect.get_width() / 2. - 0.2, 1.03 * height, '%d' % height)

total_width,n = 0.4,2
width = total_width/n

with open(r'/Users/binryang/Desktop/运行结果/balloons_qp25_16.txt', 'r') as f:
    for line in f:
        a = line.split()
        key = int(math.ceil(float(a[1])))
        if key == 0 or key > 10:
            continue
        if a[0] == '0':
            if key in dic0.keys():
                dic0[key] = dic0[key] + 1
            else:
                dic0[key] = 1
        else:
            if key+width in dic1.keys():
                dic1[key+width] = dic1[key+width] + 1
            else:
                dic1[key+width] = 1


# items0 = dic0.items()
# items0.sort()
#
# items1 = dic1.items()
# items1.sort()
#
# print dic0
# print dic1

# plt.figure()
# plt.plot(dic0.keys(),dic0.values())
# plt.plot(dic1.keys(),dic1.values())

m = plt.bar(dic0.keys(), dic0.values(),width,label='no-division')
n = plt.bar(dic1.keys(),dic1.values(),width,label='division')
autolabel(m)
autolabel(n)
plt.xlabel('difference value')
plt.ylabel('numbers')
plt.title('numbers of difference value')
plt.legend()

# plt.xticks(dic0.keys())

# plt.subplot(212)
# plt.bar(dic1.keys(),dic1.values())
# plt.xlabel('difference value')
# plt.ylabel('numbers')
# plt.xticks(dic1.keys())
plt.savefig('bar.pdf')
plt.show()

生成的图片如下：

吐槽一下：插入图片不能用pdf，导致放大失真严重