python中如何画火山图

1、导入数据

importpandasaspd#Dataanalysis

importnumpyasnp#Scientificcomputing

importseabornassns#Statisticalvisualization

#读取数据

df=pd.read_csv('./dataset_volcano.txt',sep='\t')

result=pd.DataFrame()

result['x']=df['logFC']

result['y']=df['P.Value']

result['-log10(pvalue)']=-df['P.Value'].apply(np.log10)

2、设置阈值

#设置pvalue和logFC的阈值

cut_off_pvalue=0.0000001

cut_off_logFC=1

3、设置分组

#分组为up,normal,down

result.loc[(result.x>cut_off_logFC)&(result.y

result.loc[(result.x<-cut_off_logFC)&(result.y

result.loc[(result.x>=-cut_off_logFC)&(result.x<=cut_off_logFC)|(result.y>=cut_off_pvalue),'group']='normal'

4、绘制散点图

#绘制散点图

ax=sns.scatterplot(x="x",y="-log10(pvalue)",

hue='group',

hue_order=('down','normal','up'),

palette=("#377EB8","grey","#E41A1C"),

alpha=0.5,

s=15,

5、设置散点图

#确定坐标轴显示范围

xmin=-6

xmax=10

ymin=7

ymax=13

ax.spines['right'].set_visible(False)#去掉右边框

ax.spines['top'].set_visible(False)#去掉上边框

ax.vlines(-cut_off_logFC,ymin,ymax,color='dimgrey',linestyle='dashed',linewidth=1)#画竖直线

ax.vlines(cut_off_logFC,ymin,ymax,color='dimgrey',linestyle='dashed',linewidth=1)#画竖直线

ax.hlines(-np.log10(cut_off_pvalue),xmin,xmax,color='dimgrey',linestyle='dashed',linewidth=1)#画竖水平线

ax.set_xticks(range(xmin,xmax,4))#设置x轴刻度

ax.set_yticks(range(ymin,ymax,2))#设置y轴刻度

ax.set_ylabel('-log10(pvalue)',fontweight='bold')#设置y轴标签

ax.set_xlabel('log2(foldchange)',fontweight='bold')#设置x轴标签

以上就是python中画火山图的方法，希望能对大家有所帮助，更多Python学习教程请关注IT培训机构:千锋教育。

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