无法压缩Python元组以获取绘图轴值

Question

我想为绘图的X，Y值解压缩元组，如果新元组中的项由3个组件组成（'AXIN'，37，'reported'），而不是2（AXIN，37），这会给我一个错误。在

错误表示要解压缩的多个值

new = (('AXIN', 37, 'reported'),
 ('LGR', 30, 'reported'),
 ('NK', 24, 'reported'),
 ('TN', 23, 'reported'),
 ('CC', 19, 'reported'),
 ('APC', 18, 'reported'),
 ('TRD@', 16, 'reported'),
 ('TOX', 15, 'UNREPORTED'), 
 ('LEF', 15, 'reported'),
 ('MME', 13, 'reported'),
 ('NOTUM', 13, 'reported'),
 ('PLCB', 13, 'UNREPORTED'), 
 ('GN', 11,  'UNREPORTED'),
 ('LOX', 10,  'UNREPORTED'),
 ('LOX', 10, 'reported'),
 ('CRND', 10, 'reported'),
 ('LRP', 9, 'reported'),
 ('BMP', 9, 'reported'),
 ('VSNL', 8,  'UNREPORTED'),
 ('LOC', 8, 'reported'),
 ('ZNRF', 8, 'reported'),
 ('KRT', 8,  'UNREPORTED'),
 ('CTNN', 8, 'reported'))


X, Y = zip(*new)
import seaborn as sns
sns.set()
import matplotlib.pyplot as plt 
%matplotlib inline
plt.figure(figsize = (20, 10))
mytitle = "Most common genes coexpressed with {gene1}, {gene2}, {gene3}, {gene4}".format(gene1="axin2", gene2="lef", gene3="nkd1", gene4="lgr5")
plt.title(mytitle, fontsize=40)
plt.ylabel('Number of same gene encounters across studies', fontsize=20)
ax = plt.bar(range(len(X)), Y, 0.6, align='center', tick_label = X, color="green") 
ax = plt.xticks(rotation=90)
new = tuple(new)
import networkx as nx
children = sorted(new, key=lambda x: x[1])
parent = children.pop()[0]

G = nx.Graph()
for child, weight in children: G.add_edge(parent, child, weight=weight)
width = list(nx.get_edge_attributes(G, 'weight').values())
colors = []
for i in new:
        if i[2] == 'UNREPORTED':
                colors.append('green')
        elif i[2] == 'REPORTED':
                colors.append('yellow')
nx.draw_networkx(G, font_size=10, node_size=2000, alpha=0.6, node_color=colors)
plt.savefig("plt.gene-expression.pdf")
plt.figure(figsize = (20, 10))
mytitle = "Most common genes coexpressed with {gene1}, {gene2}, {gene3}, {gene4}".format(gene1="axin2", gene2="lef", gene3="nkd1", gene4="lgr5")
plt.title(mytitle, fontsize=40)
nx.draw_networkx(G, font_size=10, node_size=2000, alpha=0.6)  #width=width is very fat lines
plt.savefig("gene-expression-graph.pdf")

ValueError: too many values to unpack (expected 2)

Answer 1

确实，有太多的值需要解包。您只给了两个变量来解压，但是每个元组有三个值。试着给它另一个变量：

X, Y, Notes = zip(*new)

现在它已经完全打开了。如果不想使用第三个组件，可以给它一个从未使用过的变量名。或者使用_，这在Python中是“nevermind”或“don't care”：

^{pr2}$

我对这个约定的唯一保留意见是，在交互使用中（例如IPython、Jupyter Notebook或stock Python interactive REPL），_也意味着“最后产生的值”。这有时与“不关心”的解释相冲突。在

顺便说一句，你也需要在你的代码中使用同样的技巧，这同样存在“要解包的项目数量错误”的问题：

for child, weight, _ in children:
    ...

这些改变，在排行榜上赫然出现：