Python的 plot函數和繪圖參數設置

python的plot函數參數很多，其中主要有：

plot([x], y, [fmt], data=None, **kwargs)
plot([x], y, [fmt], [x2], y2, [fmt2], ..., **kwargs)

 Parameters
        ----------
        x, y : array-like or scalar
            The horizontal / vertical coordinates of the data points.
            *x* values are optional. If not given, they default to
            ``[0, ..., N-1]``.

            Commonly, these parameters are arrays of length N. However,
            scalars are supported as well (equivalent to an array with
            constant value).

            The parameters can also be 2-dimensional. Then, the columns
            represent separate data sets.

        fmt : str, optional
            A format string, e.g. 'ro' for red circles. See the *Notes*
            section for a full description of the format strings.

            Format strings are just an abbreviation for quickly setting
            basic line properties. All of these and more can also be
            controlled by keyword arguments.

而在使用的時候，參數格式有：

1. fmt 參數：

 **Format Strings**
        A format string consists of a part for color, marker and line::
            fmt = '[color][marker][line]'

2. color 參數：

        **Colors**
        The following color abbreviations are supported:
        =============    ===============================
        character        color
        =============    ===============================
        ``'b'``          blue
        ``'g'``          green
        ``'r'``          red
        ``'c'``          cyan
        ``'m'``          magenta
        ``'y'``          yellow
        ``'k'``          black
        ``'w'``          white
        =============    ===============================

        If the color is the only part of the format string, you can
        additionally use any  `matplotlib.colors` spec, e.g. full names
        (``'green'``) or hex strings (``'#008000'``).

3. marker 參數：

        **Markers**
        =============    ===============================
        character        description
        =============    ===============================
        ``'.'``          point marker
        ``','``          pixel marker
        ``'o'``          circle marker
        ``'v'``          triangle_down marker
        ``'^'``          triangle_up marker
        ``'<'``          triangle_left marker
        ``'>'``          triangle_right marker
        ``'1'``          tri_down marker
        ``'2'``          tri_up marker
        ``'3'``          tri_left marker
        ``'4'``          tri_right marker
        ``'s'``          square marker
        ``'p'``          pentagon marker
        ``'*'``          star marker
        ``'h'``          hexagon1 marker
        ``'H'``          hexagon2 marker
        ``'+'``          plus marker
        ``'x'``          x marker
        ``'D'``          diamond marker
        ``'d'``          thin_diamond marker
        ``'|'``          vline marker
        ``'_'``          hline marker
        =============    ===============================

4. linestyle 參數：

        **Line Styles**
        =============    ===============================
        character        description
        =============    ===============================
        ``'-'``          solid line style
        ``'--'``         dashed line style
        ``'-.'``         dash-dot line style
        ``':'``          dotted line style
        =============    ===============================

5. 而繪圖參數非常多，部分詳細介紹可見：https://www.cnblogs.com/qi-yuan-008/p/12588121.html

6. 以下用一個例子來說明，可能更快一些：

import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure(1)

x2 = np.linspace(-0.2, 2, 10)
y2 = x2 + 0.3
plt.plot(x2, y2, color="red", linewidth=1.0, marker = 's', linestyle="--")
# plt.plot(x2, y2, color="#ef5492", linewidth=2.0, marker = 's', linestyle="--")  #也可
# plt.plot(x2, y2, 'rs--')                                                        #也可
         
#設置X軸標簽
plt.xlabel('X坐標')
#設置Y軸標簽
plt.ylabel('Y坐標')

plt.title('test繪圖函數')

#設置圖標
#plt.legend('繪圖值', loc=2, fontsize = 5)
#  The relative size of legend markers compared with the originally drawn ones.
plt.legend(['繪圖值'], loc='upper left', markerscale = 0.5, fontsize = 10)

# 設置橫軸的上下限
plt.xlim(-0.5, 2.5)
# 設置縱軸的上下限
plt.ylim(-0.5, 2.5)

# 設置橫軸精准刻度
plt.xticks(np.arange(-0.5, 2.5, step=0.5))
# 設置縱軸精准刻度
plt.yticks(np.arange(-0.5, 2.5, step=0.5))

#plt.annotate("(" + str(round(x[2],2)) +", "+ str(round(y[2],2)) +")", xy=(x[2], y[2]), fontsize=10, xycoords='data')  
plt.annotate("({0},{1})".format(round(x2[2],2), round(y2[2],2)), xy=(x2[2], y2[2]), fontsize=10, xycoords='data')
# xycoords='data' 以data值為基准 
# 設置字體大小為 10

plt.text(round(x2[6],2), round(y2[6],2), "good point", fontdict={'size': 10, 'color': 'red'})  # fontdict設置文本字體
# Add text to the axes.

plt.rcParams['font.sans-serif']=['SimHei'] #用來正常顯示中文標簽
plt.rcParams['axes.unicode_minus']=False #用來正常顯示負號

plt.savefig('test_xx.png', dpi=100, transparent=False)
# dpi: The resolution in dots per inch
#  If *True*, the axes patches will all be transparent

plt.show()

##

參考：

https://blog.csdn.net/u014636245/article/details/82799573

https://matplotlib.org/api/_as_gen/matplotlib.pyplot.figure.html#matplotlib.pyplot.figure

https://www.jianshu.com/p/78ba36dddad8

https://blog.csdn.net/u010852680/article/details/77770097

https://blog.csdn.net/u013634684/article/details/49646311