ValueError: Invalid RGBA argument: nan

ValueError: Invalid RGBA argument: nan

当我尝试绘制具有 1000 个节点的图形时出现错误。原因似乎是由于

事实上我可以在映射器中看到一些 nan 值:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
~/opt/anaconda3/lib/python3.8/site-packages/matplotlib/axes/_axes.py in _parse_scatter_color_args(c, edgecolors, kwargs, xsize, get_next_color_func)
   4290             try:  # Is 'c' acceptable as PathCollection facecolors?
-> 4291                 colors = mcolors.to_rgba_array(c)
   4292             except (TypeError, ValueError) as err:

~/opt/anaconda3/lib/python3.8/site-packages/matplotlib/colors.py in to_rgba_array(c, alpha)
    340     else:
--> 341         return np.array([to_rgba(cc, alpha) for cc in c])
    342 

~/opt/anaconda3/lib/python3.8/site-packages/matplotlib/colors.py in <listcomp>(.0)
    340     else:
--> 341         return np.array([to_rgba(cc, alpha) for cc in c])
    342 

~/opt/anaconda3/lib/python3.8/site-packages/matplotlib/colors.py in to_rgba(c, alpha)
    188     if rgba is None:  # Suppress exception chaining of cache lookup failure.
--> 189         rgba = _to_rgba_no_colorcycle(c, alpha)
    190         try:

~/opt/anaconda3/lib/python3.8/site-packages/matplotlib/colors.py in _to_rgba_no_colorcycle(c, alpha)
    262     if not np.iterable(c):
--> 263         raise ValueError(f"Invalid RGBA argument: {orig_c!r}")
    264     if len(c) not in [3, 4]:

ValueError: Invalid RGBA argument: nan

然后

ValueError: 'c' argument must be a color, a sequence of colors, or a sequence of numbers, not dict_values(['#0010ff', '#40ffb7', '#00a4ff', '#40ffb7', '#00a4ff', '#40ffb7', '#ffb900', '#0010ff', nan, '#000080', '#000080', '#000080', '#000080', nan, '#0010ff', '#0010ff', '#800000', '#0010ff', '#0010ff', '#ff3000', '#0010ff', nan, '#00a4ff', '#0010ff', '#0010ff', '#ff3000', nan, nan, '#000080', '#0010ff', '#0010ff', '#0010ff', nan, nan, '#0010ff', nan, nan, '#0010ff', '#0010ff', nan, '#40ffb7', '#00a4ff', '#00a4ff', '#00a4ff', '#0010ff', '#0010ff', '#0010ff', nan, '#800000', nan])

代码(来自)。请注意下面的代码是有效的,但是当我扩展节点数>500时,会出现上面的错误:

import networkx as nx
import numpy as np
import pandas as pd
from matplotlib import pyplot as plt, colors as mcolor

# Sample DataFrames
df1 = pd.DataFrame({
    'Node': ['A', 'A', 'B', 'B', 'B', 'Z'],
    'Edge': ['B', 'D', 'N', 'A', 'X', 'C']
})
df2 = pd.DataFrame({
    'Nodes': ['A', 'B', 'C', 'D', 'N', 'S', 'X'],
    'Attribute': [-1, 0, -1.5, 1, 1, 9, 0]
})

# Simplified construction of `colour_map`
uni_val = df2['Attribute'].unique()
colors = plt.cm.jet(np.linspace(0, 1, len(uni_val)))
# Map colours to_hex then zip with
mapper = dict(zip(uni_val, map(mcolor.to_hex, colors)))

G = nx.from_pandas_edgelist(df1, source='Node', target='Edge')
# Create Colour map. Ensure all nodes have a value via reindex
color_map = (
    df2.set_index('Nodes')['Attribute'].map(mapper)
        .reindex(G.nodes(), fill_value='black')
)
# Add Attribute to each node
nx.set_node_attributes(G, color_map, name="colour")

# Then draw with colours based on attribute values:
nx.draw(G,
        node_color=nx.get_node_attributes(G, 'colour').values(),
        with_labels=True)

plt.show()

我不知道如何在 nan 值的情况下使用 if 条件来避免 ValueError 消息并正确地将节点与其颜色相关联。希望您能提供一些帮助。

即使有 1000 个节点,您的代码也适用于我,试试 运行 这个:

    import networkx as nx
    import numpy as np
    import pandas as pd
    from matplotlib import pyplot as plt, colors as mcolor

    G = nx.fast_gnp_random_graph(1000,0.05)
    df2 = pd.DataFrame({
        'Nodes': [i for i in G.nodes()],
        'Attribute': [np.random.rand()*9 for i in G.nodes()]
    })
    # Simplified construction of `colour_map`
    uni_val = df2['Attribute'].unique()
    colors = plt.cm.jet(np.linspace(0, 1, len(uni_val)))
    # Map colours to_hex then zip with
    mapper = dict(zip(uni_val, map(mcolor.to_hex, colors)))

    # Create Colour map. Ensure all nodes have a value via reindex
    color_map = (
        df2.set_index('Nodes')['Attribute'].map(mapper)
            .reindex(G.nodes(), fill_value='black')
    )
    # Add Attribute to each node

    print(color_map)
    nx.set_node_attributes(G, color_map, name="colour")

    # Then draw with colours based on attribute values:
    nx.draw(G,
            node_color=nx.get_node_attributes(G, 'colour').values(),
            with_labels=True)

    plt.show()