内容摘要：
1、探索Matplotlib针对单条或duotiao直线的基本绘图能力。
2、添加信息，诸如说明、轴标签及标题。
3、保存图片到文件。
4、描述与IPython的交互。
5、通过配置文件及Python代码定制Matplotlib。
采用Matplotlib绘制的第一幅图
S C:\Users\guyuling> ipython
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)]
Type 'copyright', 'credits' or 'license' for more information
IPython 7.7.0 -- An enhanced Interactive Python. Type '?' for help.
In [1]: import matplotlib.pyplot as plt
In [2]: plt.plot([1,3,2,4])
Out[2]: [<matplotlib.lines.Line2D at 0x1df5bd0ac50>]
In [3]: plt.show()
实际上是1、3、2、4垂直坐标点绘直线。
image.png
In [1]: import matplotlib.pyplot as plt
In [2]: x=range(6)
In [3]: plt.plot(x,[xi**2 for xi in x])
Out[3]: [<matplotlib.lines.Line2D at 0x197324e62b0>]
In [4]: plt.show()
image.png
In [5]: import matplotlib.pyplot as plt
In [6]: import numpy as np
In [7]: x = np.arange(0.0,6.0,0.01)
In [8]: plt.plot(x,[x**2 for x in x])
Out[8]: [<matplotlib.lines.Line2D at 0x19738826cf8>]
In [9]: plt.show()
image.png
多线图
In [10]: import matplotlib.pyplot as plt
In [11]: x=range(1,5)
In [12]: plt.plot(x,[xi*1.5 for xi in x])
Out[12]: [<matplotlib.lines.Line2D at 0x1973886b0b8>]
In [13]: plt.plot(x,[xi*3.0 for xi in x])
Out[13]: [<matplotlib.lines.Line2D at 0x19738855e80>]
In [14]: plt.plot(x,[xi/3.0 for xi in x])
Out[14]: [<matplotlib.lines.Line2D at 0x197389c8ba8>]
In [15]: plt.show()
image.png
大致介绍下NumPy数组
网格、轴和标签
添加网格
plt.grid(True)
对轴进行处理
plt.axis() #显示当前轴限制值
plt.axis([0,5,-1,13]) #设置新的轴限制
添加轴标签
plt.xlabel('This is the X axis')
plt.ylabel('This is the Y axis')
标题和后端
一个完整的例子
In [1]: import matplotlib.pyplot as plt
In [2]: import numpy as np
In [3]: x=np.arange(1,5)
In [4]: plt.plot(x,x*1.5,label='Normal')
Out[4]: [<matplotlib.lines.Line2D at 0x1addaa1abe0>]
In [5]: plt.plot(x,x*3.0,label='Fast')
Out[5]: [<matplotlib.lines.Line2D at 0x1addaa65358>]
In [6]: plt.plot(x,x/3.0,label='Slow')
Out[6]: [<matplotlib.lines.Line2D at 0x1addaa79dd8>]
In [7]: plt.grid(True)
In [8]: plt.title('Sample Growth of a Measure')
Out[8]: Text(0.5, 1.0, 'Sample Growth of a Measure')
In [9]: plt.xlabel('Samples')
Out[9]: Text(0.5, 0, 'Samples')
In [10]: plt.ylabel('Values Measured')
Out[10]: Text(0, 0.5, 'Values Measured')
In [11]: plt.legend(loc='upper left')
Out[11]: <matplotlib.legend.Legend at 0x1addaaab320>
In [12]: plt.show()
image.png
保存图片到文件中
In [1]: import matplotlib.pyplot as plt
In [2]: plt.plot([1,2,3])
Out[16]: [<matplotlib.lines.Line2D at 0x1addf31df28>]
In [3]: plt.savefig('plot123.png')
交互式导航工具栏
IPython支持
ipython -pylab
plot([1,3,2,4])
控制交互模式
In [7]: import matplotlib as mpl
In [8]: mpl.rcParams['interactive']
Out[8]: False
In [9]: mpl.interactive(True)
In [10]: mpl.rcParams['interactive']
Out[10]: True
禁止函数输出
In [21]: import matplotlib.pyplot as plt
In [22]: plt.plot([1,2])
Out[22]: [<matplotlib.lines.Line2D at 0x20e74b402b0>]
In [23]: plt.plot([2,1])
Out[23]: [<matplotlib.lines.Line2D at 0x20e79623d68>]
配置Matplotlib
* Global machine configuration file
linux系统总机器配置文件在/etc/matplotlibrc
* User configure file
linux系统用户配置文件在$HOME/.matplotlib/matplotlibrc.
windows系统用户配置文件在C:\Documents and Settings\yourname.matplotlib(无总配置文件)
* Configure file in the current directory
* Python code in the current script or program or interactive session
Matplotlib有一组默认配置参数，可以按下面顺序定制：
>>>python编码的Matplotlib函数
>>>当前路径下的matplotlibrc文件
>>>用户matplotlibrc文件
>>>总的matplotlibrc文件
配置文件
backend : TkAgg
image.png
通过python代码来配置
In [29]: import matplotlib as mpl
In [30]: mpl.rcParams
Out[30]: c:\python36\lib\site-packages\IPython\lib\pretty.py:697: MatplotlibDeprecationWarning:
The examples.directory rcparam was deprecated in Matplotlib 3.0 and will be removed in 3.2. In the future, examples will be found relative to the 'datapath' directory.
output = repr(obj)
RcParams({'_internal.classic_mode': False,
'agg.path.chunksize': 0,
'animation.avconv_args': [],
'animation.avconv_path': 'avconv',
'animation.bitrate': -1,
'animation.codec': 'h264',
'animation.convert_args': [],
'animation.convert_path': 'convert',
'animation.embed_limit': 20.0,
'animation.ffmpeg_args': [],
'animation.ffmpeg_path': 'ffmpeg',
'animation.frame_format': 'png',
'animation.html': 'none',
'animation.html_args': [],
'animation.writer': 'ffmpeg',
'axes.autolimit_mode': 'data',
'axes.axisbelow': 'line',
'axes.edgecolor': 'black',
'axes.facecolor': 'white',
'axes.formatter.limits': [-7, 7],
'axes.formatter.min_exponent': 0,
'axes.formatter.offset_threshold': 4,
'axes.formatter.use_locale': False,
'axes.formatter.use_mathtext': False,
'axes.formatter.useoffset': True,
'axes.grid': False,
'axes.grid.axis': 'both',
'axes.grid.which': 'major',
'axes.labelcolor': 'black',
'axes.labelpad': 4.0,
'axes.labelsize': 'medium',
'axes.labelweight': 'normal',
'axes.linewidth': 0.8,
'axes.prop_cycle': cycler('color', ['#1f77b4', '#ff7f0e', '#2ca02c', '#d62728', '#9467bd', '#8c564b', '#e377c2', '#7f7f7f', '#bcbd22', '#17becf']),
'axes.spines.bottom': True,
'axes.spines.left': True,
'axes.spines.right': True,
'axes.spines.top': True,
'axes.titlepad': 6.0,
'axes.titlesize': 'large',
'axes.titleweight': 'normal',
'axes.unicode_minus': True,
'axes.xmargin': 0.05,
'axes.ymargin': 0.05,
'axes3d.grid': True,
'backend': 'TkAgg',
'backend_fallback': True,
'boxplot.bootstrap': None,
'boxplot.boxprops.color': 'black',
'boxplot.boxprops.linestyle': '-',
'boxplot.boxprops.linewidth': 1.0,
'boxplot.capprops.color': 'black',
'boxplot.capprops.linestyle': '-',
'boxplot.capprops.linewidth': 1.0,
'boxplot.flierprops.color': 'black',
'boxplot.flierprops.linestyle': 'none',
'boxplot.flierprops.linewidth': 1.0,
'boxplot.flierprops.marker': 'o',
'boxplot.flierprops.markeredgecolor': 'black',
'boxplot.flierprops.markeredgewidth': 1.0,
'boxplot.flierprops.markerfacecolor': 'none',
'boxplot.flierprops.markersize': 6.0,
'boxplot.meanline': False,
'boxplot.meanprops.color': 'C2',
'boxplot.meanprops.linestyle': '--',
'boxplot.meanprops.linewidth': 1.0,
'boxplot.meanprops.marker': '^',
'boxplot.meanprops.markeredgecolor': 'C2',
'boxplot.meanprops.markerfacecolor': 'C2',
'boxplot.meanprops.markersize': 6.0,
'boxplot.medianprops.color': 'C1',
'boxplot.medianprops.linestyle': '-',
'boxplot.medianprops.linewidth': 1.0,
'boxplot.notch': False,
'boxplot.patchartist': False,
'boxplot.showbox': True,
'boxplot.showcaps': True,
'boxplot.showfliers': True,
'boxplot.showmeans': False,
'boxplot.vertical': True,
'boxplot.whiskerprops.color': 'black',
'boxplot.whiskerprops.linestyle': '-',
'boxplot.whiskerprops.linewidth': 1.0,
'boxplot.whiskers': 1.5,
'contour.corner_mask': True,
'contour.negative_linestyle': 'dashed',
'datapath': 'c:\\python36\\lib\\site-packages\\matplotlib\\mpl-data',
'date.autoformatter.day': '%Y-%m-%d',
'date.autoformatter.hour': '%m-%d %H',
'date.autoformatter.microsecond': '%M:%S.%f',
'date.autoformatter.minute': '%d %H:%M',
'date.autoformatter.month': '%Y-%m',
'date.autoformatter.second': '%H:%M:%S',
'date.autoformatter.year': '%Y',
'docstring.hardcopy': False,
'errorbar.capsize': 0.0,
'examples.directory': '',
'figure.autolayout': False,
'figure.constrained_layout.h_pad': 0.04167,
'figure.constrained_layout.hspace': 0.02,
'figure.constrained_layout.use': False,
'figure.constrained_layout.w_pad': 0.04167,
'figure.constrained_layout.wspace': 0.02,
'figure.dpi': 100.0,
'figure.edgecolor': 'white',
'figure.facecolor': 'white',
'figure.figsize': [6.4, 4.8],
'figure.frameon': True,
'figure.max_open_warning': 20,
'figure.subplot.bottom': 0.11,
'figure.subplot.hspace': 0.2,
'figure.subplot.left': 0.125,
'figure.subplot.right': 0.9,
'figure.subplot.top': 0.88,
'figure.subplot.wspace': 0.2,
'figure.titlesize': 'large',
'figure.titleweight': 'normal',
'font.cursive': ['Apple Chancery',
'Textile',
'Zapf Chancery',
'Sand',
'Script MT',
'Felipa',
'cursive'],
'font.family': ['sans-serif'],
'font.fantasy': ['Comic Sans MS',
'Chicago',
'Charcoal',
'Impact',
'Western',
'Humor Sans',
'xkcd',
'fantasy'],
'font.monospace': ['DejaVu Sans Mono',
'Bitstream Vera Sans Mono',
'Computer Modern Typewriter',
'Andale Mono',
'Nimbus Mono L',
'Courier New',
'Courier',
'Fixed',
'Terminal',
'monospace'],
'font.sans-serif': ['DejaVu Sans',
'Bitstream Vera Sans',
'Computer Modern Sans Serif',
'Lucida Grande',
'Verdana',
'Geneva',
'Lucid',
'Arial',
'Helvetica',
'Avant Garde',
'sans-serif'],
'font.serif': ['DejaVu Serif',
'Bitstream Vera Serif',
'Computer Modern Roman',
'New Century Schoolbook',
'Century Schoolbook L',
'Utopia',
'ITC Bookman',
'Bookman',
'Nimbus Roman No9 L',
'Times New Roman',
'Times',
'Palatino',
'Charter',
'serif'],
'font.size': 10.0,
'font.stretch': 'normal',
'font.style': 'normal',
'font.variant': 'normal',
'font.weight': 'normal',
'grid.alpha': 1.0,
'grid.color': '#b0b0b0',
'grid.linestyle': '-',
'grid.linewidth': 0.8,
'hatch.color': 'black',
'hatch.linewidth': 1.0,
'hist.bins': 10,
'image.aspect': 'equal',
'image.cmap': 'viridis',
'image.composite_image': True,
'image.interpolation': 'nearest',
'image.lut': 256,
'image.origin': 'upper',
'image.resample': True,
'interactive': True,
'keymap.all_axes': ['a'],
'keymap.back': ['left', 'c', 'backspace', 'MouseButton.BACK'],
'keymap.copy': ['ctrl+c', 'cmd+c'],
'keymap.forward': ['right', 'v', 'MouseButton.FORWARD'],
'keymap.fullscreen': ['f', 'ctrl+f'],
'keymap.grid': ['g'],
'keymap.grid_minor': ['G'],
'keymap.help': ['f1'],
'keymap.home': ['h', 'r', 'home'],
'keymap.pan': ['p'],
'keymap.quit': ['ctrl+w', 'cmd+w', 'q'],
'keymap.quit_all': ['W', 'cmd+W', 'Q'],
'keymap.save': ['s', 'ctrl+s'],
'keymap.xscale': ['k', 'L'],
'keymap.yscale': ['l'],
'keymap.zoom': ['o'],
'legend.borderaxespad': 0.5,
'legend.borderpad': 0.4,
'legend.columnspacing': 2.0,
'legend.edgecolor': '0.8',
'legend.facecolor': 'inherit',
'legend.fancybox': True,
'legend.fontsize': 'medium',
'legend.framealpha': 0.8,
'legend.frameon': True,
'legend.handleheight': 0.7,
'legend.handlelength': 2.0,
'legend.handletextpad': 0.8,
'legend.labelspacing': 0.5,
'legend.loc': 'best',
'legend.markerscale': 1.0,
'legend.numpoints': 1,
'legend.scatterpoints': 1,
'legend.shadow': False,
'legend.title_fontsize': None,
'lines.antialiased': True,
'lines.color': 'C0',
'lines.dash_capstyle': 'butt',
'lines.dash_joinstyle': 'round',
'lines.dashdot_pattern': [6.4, 1.6, 1.0, 1.6],
'lines.dashed_pattern': [3.7, 1.6],
'lines.dotted_pattern': [1.0, 1.65],
'lines.linestyle': '-',
'lines.linewidth': 1.5,
'lines.marker': 'None',
'lines.markeredgecolor': 'auto',
'lines.markeredgewidth': 1.0,
'lines.markerfacecolor': 'auto',
'lines.markersize': 6.0,
'lines.scale_dashes': True,
'lines.solid_capstyle': 'projecting',
'lines.solid_joinstyle': 'round',
'markers.fillstyle': 'full',
'mathtext.bf': 'sans:bold',
'mathtext.cal': 'cursive',
'mathtext.default': 'it',
'mathtext.fallback_to_cm': True,
'mathtext.fontset': 'dejavusans',
'mathtext.it': 'sans:italic',
'mathtext.rm': 'sans',
'mathtext.sf': 'sans',
'mathtext.tt': 'monospace',
'patch.antialiased': True,
'patch.edgecolor': 'black',
'patch.facecolor': 'C0',
'patch.force_edgecolor': False,
'patch.linewidth': 1.0,
'path.effects': [],
'path.simplify': True,
'path.simplify_threshold': 0.1111111111111111,
'path.sketch': None,
'path.snap': True,
'pdf.compression': 6,
'pdf.fonttype': 3,
'pdf.inheritcolor': False,
'pdf.use14corefonts': False,
'pgf.preamble': '',
'pgf.rcfonts': True,
'pgf.texsystem': 'xelatex',
'polaraxes.grid': True,
'ps.distiller.res': 6000,
'ps.fonttype': 3,
'ps.papersize': 'letter',
'ps.useafm': False,
'ps.usedistiller': False,
'savefig.bbox': None,
'savefig.directory': '~',
'savefig.dpi': 'figure',
'savefig.edgecolor': 'white',
'savefig.facecolor': 'white',
'savefig.format': 'png',
'savefig.frameon': True,
'savefig.jpeg_quality': 95,
'savefig.orientation': 'portrait',
'savefig.pad_inches': 0.1,
'savefig.transparent': False,
'scatter.edgecolors': 'face',
'scatter.marker': 'o',
'svg.fonttype': 'path',
'svg.hashsalt': None,
'svg.image_inline': True,
'text.antialiased': True,
'text.color': 'black',
'text.hinting': 'auto',
'text.hinting_factor': 8,
'text.latex.preamble': '',
'text.latex.preview': False,
'text.latex.unicode': True,
'text.usetex': False,
'timezone': 'UTC',
'tk.window_focus': False,
'toolbar': 'toolbar2',
'verbose.fileo': 'sys.stdout',
'verbose.level': 'silent',
'webagg.address': '127.0.0.1',
'webagg.open_in_browser': True,
'webagg.port': 8988,
'webagg.port_retries': 50,
'xtick.alignment': 'center',
'xtick.bottom': True,
'xtick.color': 'black',
'xtick.direction': 'out',
'xtick.labelbottom': True,
'xtick.labelsize': 'medium',
'xtick.labeltop': False,
'xtick.major.bottom': True,
'xtick.major.pad': 3.5,
'xtick.major.size': 3.5,
'xtick.major.top': True,
'xtick.major.width': 0.8,
'xtick.minor.bottom': True,
'xtick.minor.pad': 3.4,
'xtick.minor.size': 2.0,
'xtick.minor.top': True,
'xtick.minor.visible': False,
'xtick.minor.width': 0.6,
'xtick.top': False,
'ytick.alignment': 'center_baseline',
'ytick.color': 'black',
'ytick.direction': 'out',
'ytick.labelleft': True,
'ytick.labelright': False,
'ytick.labelsize': 'medium',
'ytick.left': True,
'ytick.major.left': True,
'ytick.major.pad': 3.5,
'ytick.major.right': True,
'ytick.major.size': 3.5,
'ytick.major.width': 0.8,
'ytick.minor.left': True,
'ytick.minor.pad': 3.4,
'ytick.minor.right': True,
'ytick.minor.size': 2.0,
'ytick.minor.visible': False,
'ytick.minor.width': 0.6,
'ytick.right': False})
直接采用代码修改字典：
mpl.rcParams['<param name>'] = <value>
matplotlib.rcdefaults(): 恢复Matplotlib的默认配置参数值
matplotlib.rc()： 在单条命令中设置多条设置
例如：
mpl.rc(('figure','savefig'),facecolor='r')
等价于：
mpl.rcParam['figure.facecolor'] = 'r'
mpl.rcParam['savefig.facecolor'] = 'r'
mpl.rc('line',linewidth=4,linecolor='b')
等价于：
mpl.rcParam['line.linewidth'] = 4
mpl.rcParam['line.linecolor'] = 'b'
Select backend from code
In [31]: import matplotlib as mpl
In [32]: mpl.use('TkAgg')
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