• 简单回答 *

要访问ggplot样式中使用的颜色，可以执行以下操作

In [37]: import matplotlib.pyplot as plt                                                  

In [38]: plt.style.use('ggplot')                                                          

In [39]: colors = plt.rcParams['axes.prop_cycle'].by_key()['color']                       

In [40]: print('\n'.join(color for color in colors))                                      
#E24A33
#348ABD
#988ED5
#777777
#FBC15E
#8EBA42
#FFB5B8

在上例中，颜色作为RGB字符串包含在列表colors中。
记住在访问颜色列表之前调用plt.style.use(...)，否则您将找到标准颜色。

• 更详细的解释 *

上面的答案是为Matplotlib的现代版本量身定制的，其中绘图颜色和可能的其他绘图属性，如线宽和破折号（参见this answer of mine）存储在rcParams字典中，关键字为'axes.prop_cycle'，并包含在一种新的对象cycler中（cycler的另一种解释包含在我上面引用的答案中）。
要获得颜色列表，我们必须从rcParams获得cycler，然后使用它的.by_key()方法

Signature: c.by_key()
Docstring: Values by key

This returns the transposed values of the cycler.  Iterating
over a `Cycler` yields dicts with a single value for each key,
this method returns a `dict` of `list` which are the values
for the given key.

The returned value can be used to create an equivalent `Cycler`
using only `+`.

Returns
-------
transpose : dict
    dict of lists of the values for each key.

得到一个值的字典，最后，我们使用关键字'color'来索引该字典。

• 增编 *

2023年1月1日更新。
use('a_style')并不一定要访问它的颜色，颜色（可能）是在存储在字典matplotlib.style.library中的matplotlib.RcParams对象中定义的。
例如，让我们打印在不同样式中定义的所有颜色序列

In [23]: for style in sorted(plt.style.library):
    ...:     the_rc = plt.style.library[style]
    ...:     if 'axes.prop_cycle' in the_rc:
    ...:         colors = the_rc['axes.prop_cycle'].by_key()['color']
    ...:         print('%25s: %s'%(style, ', '.join(color for color in colors)))
    ...:     else:
    ...:         print('%25s: this style does not modify colors'%style)
          Solarize_Light2: #268BD2, #2AA198, #859900, #B58900, #CB4B16, #DC322F, #D33682, #6C71C4
      _classic_test_patch: this style does not modify colors
             _mpl-gallery: this style does not modify colors
      _mpl-gallery-nogrid: this style does not modify colors
                      bmh: #348ABD, #A60628, #7A68A6, #467821, #D55E00, #CC79A7, #56B4E9, #009E73, #F0E442, #0072B2
                  classic: b, g, r, c, m, y, k
          dark_background: #8dd3c7, #feffb3, #bfbbd9, #fa8174, #81b1d2, #fdb462, #b3de69, #bc82bd, #ccebc4, #ffed6f
                     fast: this style does not modify colors
          fivethirtyeight: #008fd5, #fc4f30, #e5ae38, #6d904f, #8b8b8b, #810f7c
                   ggplot: #E24A33, #348ABD, #988ED5, #777777, #FBC15E, #8EBA42, #FFB5B8
                grayscale: 0.00, 0.40, 0.60, 0.70
                  seaborn: #4C72B0, #55A868, #C44E52, #8172B2, #CCB974, #64B5CD
           seaborn-bright: #003FFF, #03ED3A, #E8000B, #8A2BE2, #FFC400, #00D7FF
       seaborn-colorblind: #0072B2, #009E73, #D55E00, #CC79A7, #F0E442, #56B4E9
             seaborn-dark: this style does not modify colors
     seaborn-dark-palette: #001C7F, #017517, #8C0900, #7600A1, #B8860B, #006374
         seaborn-darkgrid: this style does not modify colors
             seaborn-deep: #4C72B0, #55A868, #C44E52, #8172B2, #CCB974, #64B5CD
            seaborn-muted: #4878CF, #6ACC65, #D65F5F, #B47CC7, #C4AD66, #77BEDB
         seaborn-notebook: this style does not modify colors
            seaborn-paper: this style does not modify colors
           seaborn-pastel: #92C6FF, #97F0AA, #FF9F9A, #D0BBFF, #FFFEA3, #B0E0E6
           seaborn-poster: this style does not modify colors
             seaborn-talk: this style does not modify colors
            seaborn-ticks: this style does not modify colors
            seaborn-white: this style does not modify colors
        seaborn-whitegrid: this style does not modify colors
     tableau-colorblind10: #006BA4, #FF800E, #ABABAB, #595959, #5F9ED1, #C85200, #898989, #A2C8EC, #FFBC79, #CFCFCF

在我看来，

• 不修改颜色的seaborn-xxx样式将用作样式序列中的最后一步，例如plt.style.use(['seaborn', 'seaborn-poster'])或plt.style.use(['seaborn', 'seaborn-muted', 'seaborn-poster'])
• _起始样式也意味着修改其它样式，并且
• 唯一的另一个风格，fast，不修改颜色是所有关于调整渲染参数，以具有 * 更快 * 的渲染。