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社区首页 >问答首页 >熊猫,连列值。

熊猫,连列值。
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Stack Overflow用户
提问于 2018-10-18 15:12:43
回答 2查看 180关注 0票数 0

我以前在这里找到了这个问题的答案,但似乎没有一个对我有用。现在我有一个数据框架,上面有客户的列表和他们的地址。但是,每个地址都被分隔成多个列,我试图将它们放在一个列下。

到目前为止,我读到的代码是这样的:

代码语言:javascript
复制
data1_df['Address'] = data1_df['Address 1'].map(str) + ", " + data1_df['Address 2'].map(str) + ", " +  data1_df['Address 3'].map(str) + ", " + data1_df['city'].map(str) + ", " +  data1_df['city'].map(str) + ", " +  data1_df['Province/State'].map(str) + ", " +  data1_df['Country'].map(str) + ", " +  data1_df['Postal Code'].map(str)  

但是,我得到的错误是: TypeError:一元加期望数字dtype,而不是object

我不知道为什么它不接受字符串的原样并使用+操作符。加号不应该容纳对象吗?

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回答 2

Stack Overflow用户

回答已采纳

发布于 2018-10-18 15:17:09

希望您会发现这个例子很有帮助:

代码语言:javascript
复制
import pandas as pd
import numpy as np

df = pd.DataFrame({'A': [1,2,3],
                   'B': list('ABC'),
                   'C': [4,5,np.nan],
                   'D': ['One', np.nan, 'Three']})

addColumns = ['B', 'C', 'D']

df['Address'] = df[addColumns].astype(str).apply(lambda x: ', '.join([i for i in x if i != 'nan']), axis=1)

df

#   A  B    C      D      Address
#0  1  A  4.0    One  A, 4.0, One
#1  2  B  5.0    NaN       B, 5.0
#2  3  C  NaN  Three     C, Three

上面的工作方式是str表示NaNnan

也可以用空字符串填充NaN

代码语言:javascript
复制
df['Address'] = df[addColumns].fillna('').astype(str).apply(lambda x: ', '.join([i for i in x if i]), axis=1)
票数 3
EN

Stack Overflow用户

发布于 2018-10-18 17:07:47

对于需要将NaN值添加到一起的列,下面是一些逻辑:

代码语言:javascript
复制
def add_cols_w_nan(df, col_list, space_char, new_col_name):
    """ Add together multiple columns where some of the columns 
    may contain NaN, with the appropriate amount of spacing between columns. 

    Examples:
        'Mr.' + NaN + 'Smith' becomes 'Mr. Smith'
        'Mrs.' + 'J.' + 'Smith' becomes 'Mrs. J. Smith'
        NaN + 'J.' + 'Smith' becomes 'J. Smith'

    Args:
        df: pd.DataFrame
            DataFrame for which strings are added together.
        col_list: ORDERED list of column names, eg. ['first_name', 
            'middle_name', 'last_name']. The columns will be added in order. 
        space_char: str
            Character to insert between concatenation of columns.
        new_col_name: str
            Name of the new column after adding together strings.

    Returns: pd.DataFrame with a string addition column

    """
    df2 = df[col_list].copy()

    # Convert to strings, leave nulls alone
    df2 = df2.where(df2.isnull(), df2.astype('str'))

    # Add space character, NaN remains NaN, which is important
    df2.loc[:, col_list[1:]] = space_char + df2.loc[:, col_list[1:]]

    # Fix rows where leading columns are null
    to_fix = df2.notnull().idxmax(1)
    for col in col_list[1:]:
        m = to_fix == col
        df2.loc[m, col] = df2.loc[m, col].str.replace(space_char, '')

    # So that summation works
    df2[col_list] = df2[col_list].replace(np.NaN, '')

    # Add together all columns
    df[new_col_name] = df2[col_list].sum(axis=1)
    # If all are missing replace with missing
    df[new_col_name] = df[new_col_name].replace('', np.NaN)

    del df2
    return df

样本数据:

代码语言:javascript
复制
import pandas as pd
import numpy as np
df = pd.DataFrame({'Address 1': ['AAA', 'ABC', np.NaN, np.NaN, np.NaN],
                   'Address 2': ['foo', 'bar', 'baz', None, np.NaN],
                   'Address 3': [np.NaN, np.NaN, 17, np.NaN, np.NaN],
                   'city': [np.NaN, 'here', 'there', 'anywhere', np.NaN],
                   'state': ['NY', 'TX', 'WA', 'MI', np.NaN]})

#  Address 1 Address 2  Address 3      city state
#0       AAA       foo        NaN       NaN    NY
#1       ABC       bar        NaN      here    TX
#2       NaN       baz       17.0     there    WA
#3       NaN      None        NaN  anywhere    MI
#4       NaN       NaN        NaN       NaN   NaN

df = add_cols_w_nan(
    df,
    col_list = ['Address 1', 'Address 2', 'Address 3', 'city', 'state'],
    space_char = ', ',
    new_col_name = 'full_address')

df.full_address.tolist()
#['AAA, foo, NY', 
# 'ABC, bar, here, TX', 
# 'baz, 17.0, there, WA', 
# 'anywhere, MI',
# nan]
票数 0
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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/52877220

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