CODEWITHSUNDEEP
pythonpandasdataframecsv
haker146
haker146

Reputation: 69

How to add another value to a given row and column

I've been struggling with one problem for two days that I have with Python and the Pandas package. I am creating a dataframe with filtered data from another csv and then want to export it to csv again. However, I have a problem because I do not know how to add another value to a specific cell without removing the previous one so that it looks more or less like this in CSV. So that I could add this letter b to the second column and the first row where the letter a already exists

enter image description here

Upvotes: 1

Views: 1703

Answers (4)

Alireza75
Alireza75

Reputation: 501

This is very very faster and better

def f(s):
    if s.find('a')>=0:
        return s+', b'
    return s
df['B']=df['B'].apply(func=f)

Upvotes: 0

robperch
robperch

Reputation: 45

This is how I would approach the problem:

Creating example dataframe

  • Code:

    df = pd.DataFrame(
    data={
        'A': [1, 2, 3],
        'B': ['a', 'a', 'b'],
    }
)

  • Result

    df

    A   B
0   1   a
1   2   a
2   3   b

Applying function to add character (with comma) only on the rows that meet a condition

This will work for the entire 2nd column (in this example, column ‘B’).

If you’d like to apply this rule only to a specific row of the dataframe, I would only add the following:

Applying function to add character (with comma) only on the rows that meet a condition

  • Code:

    # Condition: the character 'a' has to be present on a selecteed row

row = 0 ## row where you'd like to apply the change

df.loc[row, ['B']] = df.loc[row, ['B']].apply(lambda x: x + ', b' if 'a' in x else x)

  • Result:

    df

    A   B
0   1   a, b
1   2   a
2   3   b

Hope this solutions helps!

Upvotes: 1

Alireza75
Alireza75

Reputation: 501

You can use this code It edits all of the rows if you want else you want to edit just first row you can remove for loop and use i=0

for i in df.index:
  if df['B'][i].find('a')>=0:
    df['B'][i] += ', b'

Upvotes: 1

haker146
haker146

Reputation: 69

df_10 = pd.DataFrame({'A': ['xx', '--- bios ---', 'yy', 'zz', '--- os ---'],'B': ['rat', '', 'winter', 'host','']})

I create such a data frame as add to column A and line 2, for example the value "new"

Upvotes: 1

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