Question

我有一个这样的数据框：

        nt
12062   Python Pandas: Create new column out of other columns where value is not null
12063   Python Pandas Create New Column with Groupby().Sum()
12064   
12065   Python - Pandas - create “first fail” column from other column data
12066   
12067   
12068   Creating new column in pandas based on value of other column
12070   Merge with pandas creating new columns?

我想得到的是：

如果nt列具有“Create”字，则创建一个新列（列名为CreateC），其行等于1。像这样：

        nt                                                                             CreateC
12062   Python Pandas: Create new column out of other columns where value is not null   1
12063   Python Pandas Create New Column with Groupby().Sum()                            1
12064                                                                           0
12065   Python - Pandas - create “first fail” column from other column data     1
12066                                                                           0
12067                                                                   0
12068   Creating new column in pandas based on value of other column    0
12070   Merge with pandas creating new columns?                         0

我所做的是：

我在索引上创建了一个新的列然后找到包含'创建'的行然后找到这些行的索引号

df['index1'] = df.index
dfCreate = df[df['dataframe'].str.contains("Create", na = False)]
dfCreateIndex = dfCreate.index.tolist()

def CreateCs (row):
    RowIndex1 = pd.to_numeric(row['index1'], errors='coerce')
    for i in dfCreateIndex:
        y = dfCreateIndex
        if RowIndex1 == y:
            return '1'
        else:
            return '0'
df['CreateC'] = df.apply(lambda row: CreateCs(row), axis=1)

但我只得到了：

ValueError: ('The truth value of a DataFrame is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().', 'occurred at index 0')

有什么简单的方法吗？

Answer 1

您可以将str.contains用于布尔掩码，然后将True和False转换为1，将0转换为astype至{{1然后由另一个int转换为str（如有必要）：

astype

numpy.where的另一个解决方案：

df['CreateC'] = df['nt'].str.contains('Create', case=False).astype(int).astype(str)
print (df)
                                                      nt CreateC
12062  Python Pandas: Create new column out of other ...       1
12063  Python Pandas Create New Column with Groupby()...       1
12064                                                          0
12065  Python - Pandas - create “first fail” column f...       1
12066                                                          0
12067                                                          0
12068  Creating new column in pandas based on value o...       0
12070            Merge with pandas creating new columns?       0

Python，Pandas ===＆gt;根据其他列创建新列

1 个答案: