如何从一列中提取字符串并将其保存在dataframe中的新列中？

Question

这是我的数据帧：

repository,sha1,url,refactorings
repo1,1,url1,"[{'type': 'Add Parameter', 'description': 'Add Parameter id : String in method public IssueFilter(repository Repository, id String) from class com.github.pockethub.android.core.issue.IssueFilter', 'leftSideLocations': [{'filePath': 'path2'}]]
repo2,2,url2,"[{'type': 'Add Parameter', 'description': 'Add Parameter id : String in method public IssueFilter(repository Repository, id String) from class com.github.pockethub.android.core.issue.IssueFilter', 'leftSideLocations': [{'filePath': 'path2'}]]

我想从重构列中提取：添加类型为的参数，以及类后面的com.github.pockethub.android.core.issue.IssueFilter，并将它们放在新列中，然后删除重构列

该框架是：

repository,sha1,url,refac, class
repo1,1,url1,Add Parameter, com.github.pockethub.android.core.issue.IssueFilter
repo2,2,url2,Add Parameter, com.github.pockethub.android.core.issue.IssueFilter

这是我的代码：

df= pd.read_csv('data.csv', sep=',')

df1 = df[['sha1','url','refactorings']]
df1['refac']=df.refactorings.str.extract(r'[C|c]lass\s*([^ ]*)')
df1['class']=df.refactorings.str.extract(r"type':'\s*([^ ]*)")
del df1['refactorings']
a=df1.loc[~df1.sha1.duplicated(keep='last')]

list=[]
for elm in a['sha1']:
    list.append(elm)
dicts = {key: d for key, d in df.groupby('sha1')}
lenght=len(list)
for i in range(lenght):
    output1="output"+str(i)+".csv"
    a=dicts[list[i]]
    m=pd.DataFrame.from_dict(a) 
    m.to_csv(output1, index=False, na_rep='NaN')

它没有正确地提取重构和类：对于重构它返回'Add，对于类它返回com.github.pockethub.android.core.issue.IssueFilter',，它也没有创建任何新列，也没有删除重构列

Answer 1

将regexp与str.extract()一起使用

obj = df['refactorings'].astype(str)

df['refac'] = obj.str.extract("'type': '(.*?)'")
df['class'] = obj.str.extract("from class (.*?)'")

df[['repository', 'sha1', 'url', 'refac', 'class']]