雙y軸座標軸圖

今天利用matplotlib繪圖，想要完成一個雙座標格式的圖。

fig=plt.figure(figsize=(20,15)) ax1=fig.add_subplot(111) ax1.plot(demo0719['TPS'],'b-',label='TPS',linewidth=2) ax2=ax1.twinx()#這是雙座標關鍵一步 ax2.plot(demo0719['successRate']*100,'r-',label='successRate',linewidth=2)

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fig=plt.figure(figsize=(20,15))ax1=fig.add_subplot(111)ax1.plot(demo0719['TPS'],'b-',label='TPS',linewidth=2)ax2=ax1.twinx()#這是雙座標關鍵一步ax2.plot(demo0719['successRate']*100,'r-',label='successRate',linewidth=2)

橫座標設定時間間隔

import matplotlib.dates as mdate ax1.xaxis.set_major_formatter(mdate.DateFormatter('%Y-%m-%d %H:%M:%S'))#設定時間標籤顯示格式 plt.xticks(pd.date_range(demo0719.index[0],demo0719.index[-1],freq='1min'))

123	import matplotlib.dates asmdateax1.xaxis.set_major_formatter(mdate.DateFormatter('%Y-%m-%d %H:%M:%S'))#設定時間標籤顯示格式plt.xticks(pd.date_range(demo0719.index[0],demo0719.index[-1],freq='1min'))

縱座標設定顯示百分比

import matplotlib.ticker as mtick fmt='%.2f%%' yticks = mtick.FormatStrFormatter(fmt) ax2.yaxis.set_major_formatter(yticks)

1234	import matplotlib.ticker asmtickfmt='%.2f%%'yticks=mtick.FormatStrFormatter(fmt)ax2.yaxis.set_major_formatter(yticks)

知識點

在matplotlib中，整個影象為一個Figure物件。在Figure物件中可以包含一個，或者多個Axes物件。每個Axes物件都是一個擁有自己座標系統的繪圖區域。其邏輯關係如下：

一個Figure對應一張圖片。

Title為標題。Axis為座標軸，Label為座標軸標註。Tick為刻度線，Tick Label為刻度註釋。¹

Title為標題。Axis為座標軸，Label為座標軸標註。Tick為刻度線，Tick Label為刻度註釋。

add_subplot()

The Axes instance will be returned.

twinx()

ax = twinx()

1	ax=twinx()

create a twin of Axes for generating a plot with a sharex x-axis but independent y axis. The y-axis of self will have ticks on left and the returned axes will have ticks on the right.
意思就是，建立了一個獨立的Y軸，共享了X軸。雙座標軸！

類似的還有twiny()

ax1.xaxis.set_major_formatter

Set the formatter of the major ticker
ACCEPTS: A Formatter instance

DateFormatter()

strftime方法（傳入格式化字串）。

strftime(dt, fmt=None) Refer to documentation for datetime.strftime. fmt is a strftime() format string.

123	strftime(dt,fmt=None)Refer todocumentation fordatetime.strftime.fmt isastrftime()format string.

FormatStrFormatter()

Use a new-style format string (as used by str.format()) to format the tick. The field formatting must be labeled x
定義字串格式。

plt.xticks

# return locs, labels where locs is an array of tick locations and # labels is an array of tick labels. locs, labels = xticks() # set the locations of the xticks xticks( arange(6) ) # set the locations and labels of the xticks xticks( arange(5), ('Tom', 'Dick', 'Harry', 'Sally', 'Sue') )

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# return locs, labels where locs is an array of tick locations and# labels is an array of tick labels.locs,labels=xticks()# set the locations of the xticksxticks(arange(6))# set the locations and labels of the xticksxticks(arange(5),('Tom','Dick','Harry','Sally','Sue'))

程式碼彙總

#coding:utf-8 import matplotlib.pyplot as plt import matplotlib as mpl import matplotlib.dates as mdate import matplotlib.ticker as mtick import numpy as np import pandas as pd import os mpl.rcParams['font.sans-serif']=['SimHei'] #用來正常顯示中文標籤 mpl.rcParams['axes.unicode_minus']=False #用來正常顯示負號 mpl.rc('xtick', labelsize=20) #設定座標軸刻度顯示大小 mpl.rc('ytick', labelsize=20) font_size=30 #matplotlib.rcParams.update({'font.size': 60}) %matplotlib inline plt.style.use('ggplot') data=pd.read_csv('simsendLogConvert_20160803094801.csv',index_col=0,encoding='gb2312',parse_dates=True) columns_len=len(data.columns) data_columns=data.columns for x in range(0,columns_len,2): print('第{}列'.format(x)) total=data.ix[:,x] print('第{}列'.format(x+1)) successRate=(data.ix[:,x+1]/data.ix[:,x]).fillna(0) yLeftLabel=data_columns[x] yRightLable=data_columns[x+1] print('------------------開始繪製型別{}曲線圖------------------'.format(data_columns[x])) fig=plt.figure(figsize=(25,20)) ax1=fig.add_subplot(111) #繪製Total曲線圖 ax1.plot(total,color='#4A7EBB',label=yLeftLabel,linewidth=4) # 設定X軸的座標刻度線顯示間隔 ax1.xaxis.set_major_formatter(mdate.DateFormatter('%Y-%m-%d %H:%M:%S'))#設定時間標籤顯示格式 plt.xticks(pd.date_range(data.index[0],data.index[-1],freq='1min'))#時間間隔 plt.xticks(rotation=90) #設定雙座標軸，右側Y軸 ax2=ax1.twinx() #設定右側Y軸顯示百分數 fmt='%.2f%%' yticks = mtick.FormatStrFormatter(fmt) # 繪製成功率影象 ax2.set_ylim(0,110) ax2.plot(successRate*100,color='#BE4B48',label=yRightLable,linewidth=4) ax2.yaxis.set_major_formatter(yticks) ax1.set_xlabel('Time',fontsize=font_size) ax1.set_ylabel(yLeftLabel,fontsize=font_size) ax2.set_ylabel(yRightLable,fontsize=font_size) legend1=ax1.legend(loc=(.02,.94),fontsize=16,shadow=True) legend2=ax2.legend(loc=(.02,.9),fontsize=16,shadow=True) legend1.get_frame().set_facecolor('#FFFFFF') legend2.get_frame().set_facecolor('#FFFFFF') plt.title(yLeftLabel+'&'+yRightLable,fontsize=font_size) plt.savefig('D:\\JGT\Work-YL\\01佈置的任務\\04繪製曲線圖和報告檔案\\0803\出圖\\{}-{}'.format(yLeftLabel.replace(r'/',' '),yRightLable.replace(r'/',' ')),dpi=300)

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#coding:utf-8import matplotlib.pyplot asplt import matplotlib asmplimport matplotlib.dates asmdateimport matplotlib.ticker asmtickimport numpy asnpimport pandas aspdimport osmpl.rcParams['font.sans-serif']=['SimHei']#用來正常顯示中文標籤mpl.rcParams['axes.unicode_minus']=False#用來正常顯示負號mpl.rc('xtick',labelsize=20)#設定座標軸刻度顯示大小mpl.rc('ytick',labelsize=20)font_size=30#matplotlib.rcParams.update({'font.size': 60})%matplotlibinlineplt.style.use('ggplot')data=pd.read_csv('simsendLogConvert_20160803094801.csv',index_col=0,encoding='gb2312',parse_dates=True)columns_len=len(data.columns)data_columns=data.columnsforxinrange(0,columns_len,2):print('第{}列'.format(x))total=data.ix[:,x]print('第{}列'.format(x+1))successRate=(data.ix[:,x+1]/data.ix[:,x]).fillna(0)yLeftLabel=data_columns[x]yRightLable=data_columns[x+1]print('------------------開始繪製型別{}曲線圖------------------'.format(data_columns[x]))fig=plt.figure(figsize=(25,20))ax1=fig.add_subplot(111)#繪製Total曲線圖ax1.plot(total,color='#4A7EBB',label=yLeftLabel,linewidth=4)# 設定X軸的座標刻度線顯示間隔ax1.xaxis.set_major_formatter(mdate.DateFormatter('%Y-%m-%d %H:%M:%S'))#設定時間標籤顯示格式plt.xticks(pd.date_range(data.index[0],data.index[-1],freq='1min'))#時間間隔plt.xticks(rotation=90)#設定雙座標軸，右側Y軸ax2=ax1.twinx()#設定右側Y軸顯示百分數fmt='%.2f%%'yticks=mtick.FormatStrFormatter(fmt)# 繪製成功率影象ax2.set_ylim(0,110)ax2.plot(successRate*100,color='#BE4B48',label=yRightLable,linewidth=4)ax2.yaxis.set_major_formatter(yticks)ax1.set_xlabel('Time',fontsize=font_size)ax1.set_ylabel(yLeftLabel,fontsize=font_size)ax2.set_ylabel(yRightLable,fontsize=font_size)legend1=ax1.legend(loc=(.02,.94),fontsize=16,shadow=True)legend2=ax2.legend(loc=(.02,.9),fontsize=16,shadow=True)legend1.get_frame().set_facecolor('#FFFFFF')legend2.get_frame().set_facecolor('#FFFFFF')plt.title(yLeftLabel+'&'+yRightLable,fontsize=font_size)plt.savefig('D:\\JGT\Work-YL\\01佈置的任務\\04繪製曲線圖和報告檔案\\0803\出圖\\{}-{}'.format(yLeftLabel.replace(r'/',' '),yRightLable.replace(r'/',' ')),dpi=300)

參考