python matplotlib庫基本圖形展現

python matplotlib庫基本圖形展現

• matplotlib 爲python下的一個可視化庫，它提供了很好的二維甚至三維的圖形展現接口。以下是matplotlib的一些基本數據實現方式

散點圖

import matplotlib.pyplot as plt

import numpy as np

higth = [168,178,173,165]
weight = [51,64,61,57]

# 散點圖繪製
plt.scatter(higth, weight)

# 隨機生成數據
number = 1000
x = np.random.randn(number)
y = np.random.randn(number)

# 生成離散點圖
plt.scatter(x, y)

 

# 正相關模型
y += x

plt.scatter(x,y)

 

# 生成負相關線性模型
plt.scatter(-x,y,s = 10)

關於scatter 的參數（Parameters）

• x, y : array_like, shape (n, )The data positions.

• s : scalar or array_like, shape (n, ), optionalThe marker size in points**2.Default is rcParams['lines.markersize'] ** 2.

• c : color, sequence, or sequence of color, optional, default: 'b'The marker color. Possible values:

  • A single color format string.

  • A sequence of color specifications of length n.

  • A sequence of n numbers to be mapped to colors using cmap andnorm.

  • A 2-D array in which the rows are RGB or RGBA.

  Note that c should not be a single numeric RGB or RGBA sequencebecause that is indistinguishable from an array of values to becolormapped. If you want to specify the same RGB or RGBA value forall points, use a 2-D array with a single row.

• marker : ~matplotlib.markers.MarkerStyle, optional, default: 'o'The marker style. marker can be either an instance of the classor the text shorthand for a particular marker.See ~matplotlib.markers for more information marker styles.

• cmap : ~matplotlib.colors.Colormap, optional, default: NoneA .Colormap instance or registered colormap name. cmap is onlyused if c is an array of floats. If None, defaults to rcimage.cmap.

• norm : ~matplotlib.colors.Normalize, optional, default: NoneA .Normalize instance is used to scale luminance data to 0, 1.norm is only used if c is an array of floats. If None, usethe default .colors.Normalize.

• vmin, vmax : scalar, optional, default: Nonevmin and vmax are used in conjunction with norm to normalizeluminance data. If None, the respective min and max of the colorarray is used. vmin and vmax are ignored if you pass a norminstance.

• alpha : scalar, optional, default: NoneThe alpha blending value, between 0 (transparent) and 1 (opaque).

• linewidths : scalar or array_like, optional, default: NoneThe linewidth of the marker edges. Note: The default edgecolorsis 'face'. You may want to change this as well.If None, defaults to rcParams lines.linewidth.

• verts : sequence of (x, y), optionalIf marker is None, these vertices will be used to constructthe marker. The center of the marker is located at (0, 0) innormalized units. The overall marker is rescaled by s.

• edgecolors : color or sequence of color, optional, default: 'face'The edge color of the marker. Possible values:

  • 'face': The edge color will always be the same as the face color.

  • 'none': No patch boundary will be drawn.

  • A matplotib color.

  For non-filled markers, the edgecolors kwarg is ignored andforced to 'face' internally.

折線圖

import matplotlib.dates as mdates

# 讀取數據，data:日期，open:開盤價格，收盤價格，
# 其中日期須要格式化爲 float 類型
data,open,close = np.loadtxt('../dataset/money.csv',
                             delimiter=',',
                             converters={0:mdates.strpdate2num('%Y/%m/%d')},
                             encoding='utf-8',
                             usecols=(0,1,3),unpack=True)

# plot_date(data,open) 默認爲散點圖，
# 可自動識別float 類型的 data數據，並把它轉換爲日期
plt.plot_date(data[::8],open[::8],'-',color='r',marker = 'o',markersize = '0.5')

條形圖

import matplotlib.pyplot as plt
import numpy as np

N = 5
y = [20,10,30,25,13]
index = np.arange(N)

plt.bar(left= index,height = y,color = 'red',width = 0.5,)

餅狀圖

# The silces will be ordered and plotted counter-clockwise.
labels = 'Frogs', 'Hogs', 'Dogs', 'Logs' # 定義標籤
# 每一塊的比例
sizes = [15,30,45,10] 
# 指定顏色
colors = ['yellowgreen', 'gold', 'lightskyblue', 'lightcoral'] 
# 突出顯示，這裏僅顯示第二塊
explode = (0, 0.1, 0, 0) 
​
plt.pie(sizes, explode = explode, labels = labels, colors = colors, autopct = '%1.1f%%', shadow = True, startangle = 90)
plt.axis('equal') # 顯示爲園（避免比列壓縮爲橢圓）
plt.show()

餅狀圖參數（Parameters）

• x : array-like

  • The wedge sizes.

• explode : array-like, optional, default: None

  • If not None, is a len(x) array which specifies the fractionof the radius with which to offset each wedge.

• labels : list, optional, default: None

  • A sequence of strings providing the labels for each wedge

• colors : array-like, optional, default: None

  • A sequence of matplotlib color args through which the pie chartwill cycle. If None, will use the colors in the currentlyactive cycle.

• autopct : None (default), string, or function, optional

  • If not None, is a string or function used to label the wedgeswith their numeric value. The label will be placed inside thewedge. If it is a format string, the label will be fmt%pct.If it is a function, it will be called.

• pctdistance : float, optional, default: 0.6

  • The ratio between the center of each pie slice and the start ofthe text generated by autopct. Ignored if autopct is None.

• shadow : bool, optional, default: False

  • Draw a shadow beneath the pie.

• labeldistance : float, optional, default: 1.1

  • The radial distance at which the pie labels are drawn

• startangle : float, optional, default: None

  • If not None, rotates the start of the pie chart by angledegrees counterclockwise from the x-axis.

• radius : float, optional, default: None

  • The radius of the pie, if radius is None it will be set to 1.

• counterclock : bool, optional, default: True

  • Specify fractions direction, clockwise or counterclockwise.

• wedgeprops : dict, optional, default: None

  • Dict of arguments passed to the wedge objects making the pie.

  • For example, you can pass in wedgeprops = {'linewidth': 3}to set the width of the wedge border lines equal to 3.

  • For more details, look at the doc/arguments of the wedge object.By default clip_on=False.

• textprops : dict, optional, default: None

  • Dict of arguments to pass to the text objects.

• center : list of float, optional, default: (0, 0)

  • Center position of the chart. Takes value (0, 0) or is a sequenceof 2 scalars.

• frame : bool, optional, default: False

  • Plot axes frame with the chart if true.

• rotatelabels : bool, optional, default: False

  • Rotate each label to the angle of the corresponding slice if true.