python-3.x - 如何根据条件删除pandas中的行？

Question

我有以下数据框

df = pd.DataFrame([['1','aa','ccc','rere','thth','my desc 1','','my feature2 1'], ['1','aa','fff','flfl','ipip','my desc 2','',''], ['1','aa','mmm','rprp','','','',''], ['2','aa','ccc','rprp','','','my feature1 1',''], ['2','aa','fff','bubu','thth','my desc 3','',''], ['2','aa','mmm','fafa','rtrt','my desc 4','',''], ['3','aa','ccc','blbl','thth','my desc 5','my feature1 2','my feature2 2'], ['3','aa','fff','arar','amam','my desc 6','',''], ['3','aa','mmm','acac','ryry','my desc 7','',''],['4','bb','coco','rere','','','','my feature2 3'], ['4','bb','inin','mimi','rere','my desc 8','',''], ['4','bb','itit','toto','enen','my desc 9','',''], ['4','bb','spsp','glgl','pepe','my desc 10','',''], ['5','bb','coco','baba','mpmp','my desc 11','my feature1 3',''], ['5','bb','inin','rere','','','',''],['5','bb','itit','toto','hrhr','my desc 12','',''], ['5','bb','spsp','glgl','lolo','my desc 13','','']], columns=['foo', 'bar','name_input','value_input','bulb','desc','feature1', 'feature2'])

现在，我需要删除行才能获得以下输出。

df = pd.DataFrame([['1','aa','ccc','rere','thth','my desc 1','','my feature2 1'], ['2','aa','ccc','rprp','','my desc 3','my feature1 1',''], ['3','aa','ccc','blbl','thth','my desc 5','my feature1 2','my feature2 2'], ['4','bb','coco','rere','','my desc 8','','my feature2 3'], ['5','bb','coco','baba','mpmp','my desc 11','my feature1 3','']], columns=['foo', 'bar','name_input','value_input','bulb','desc','feature1', 'feature2'])

我尝试了以下方法。但它们似乎都不起作用。

df= df.dropna(subset=['feature1', 'feature2'])
df.dropna(thresh=5, axis=0, inplace=True)
df= df[df.feature2.notnull()]
df= df[pd.notnull(df[['feature1', 'feature2']])]

非常感谢任何帮助!

Answer 1

astype(bool)

空字符串在 bool 上下文中计算结果为 False。使用 filter 仅获取以 feature 开头的列。然后使用 astype(bool) ，然后使用 any(axis=1)

df[df.filter(regex='fea').astype(bool).any(1)]

   foo bar name_input value_input  bulb        desc       feature1       feature2
0    1  aa        ccc        rere  thth   my desc 1                 my feature2 1
3    2  aa        ccc        rprp                    my feature1 1               
6    3  aa        ccc        blbl  thth   my desc 5  my feature1 2  my feature2 2
9    4  bb       coco        rere                                   my feature2 3
13   5  bb       coco        baba  mpmp  my desc 11  my feature1 3     

为了匹配您的结果，我们可以回填 desc 列

feat = df.filter(regex='feat').astype(bool).any(1)
desc = df.desc.where(df.desc.astype(bool)).bfill()
df.assign(desc=desc)[feat]

   foo bar name_input value_input  bulb        desc       feature1       feature2
0    1  aa        ccc        rere  thth   my desc 1                 my feature2 1
3    2  aa        ccc        rprp         my desc 3  my feature1 1               
6    3  aa        ccc        blbl  thth   my desc 5  my feature1 2  my feature2 2
9    4  bb       coco        rere         my desc 8                 my feature2 3
13   5  bb       coco        baba  mpmp  my desc 11  my feature1 3