python - 如果另一列包含字符串，则替换 pandas 中的一列

Question

我有两列 newlabels 和 newlabels_tobeReplaced 。如果 newlabels 的句子中包含单词“trifurcation”，则 newlabels_tobeReplaced 应替换为“trifurcation”我有以下代码

df_new.loc[df_new.newlabels.str.contains('trifurcation'),'newlabels_tobeReplaced'] = 'trifurcation'

但是，我收到此错误:

A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead

See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
self.obj[item] = s

任何想法，如何获得正确的结果。问题是，新标签的值如下:“波形表明左下肢踝关节水平休息时有轻度远端缺血的三叉疾病。”

Answer 1

您可以通过使用 assign 生成的副本重新分配给 df_new 来绕过该警告

df_new = df_new.assign(
    newlabels_tobeReplaced=
    lambda d: d['newlabels_tobeReplaced'].mask(
        d.newlabels.str.contains('trifurcation'), 'trifurcation'
    )
)