根据另一列的值在 Pandas 中创建新列

Question

The task is the following:

Add a new column to df called income10. It should contain the same values as income with all 0 values replaced with 1.

I have tried the following code:

df['income10'] = np.where(df['income']==0, df['income10'],1)

but I keep getting an error:

Answer 1

You can apply a function on each value in your column:

df["a"] = df.a.apply(lambda x: 1 if x == 0 else x)

Answer 2

You are trying to reference a column which does not exist yet.

df['income10'] = np.where(df['income']==0, ===>**df['income10']**,1)

In your np.where, you need to reference the column where the values originate. Try this instead

df['income10'] = np.where(df['income']==0, 1, df['income'])

Edit: corrected order of arguments