pandas DataFrame 某些列的中值

Question

Trying to figure out how to calculate the median for values of certain columns within a pandas DataFrame. Say for instance I have a DataFrame of 7 columns and 200 rows and I want to extract the numbers contained in columns of index 1-3 (including) and calculate the median for the total of all rows combined; for 3 rows it would be the median for (x+y+z) + (x+y+z) + (x+y+z).

I've tried:

df["median"] = df.apply(lambda x : median(x), df[2:4])

but it raises the error:

`TypeError: 'DataFrame' objects are mutable, thus they cannot be hashed

I've also tried:

x = df["column1"]
y = df["column2"]
z = df["column3"]
median_nums = [x,y,z]

but the list isn't suitable and I'm not managing to extract the numbers themselves from the DataFrame in order to used statistics.median on them. The same error as above is raised

Help would be extremely appreciated

Answer 1

You can select before median

df['New']=df.iloc[:,2:4].median(axis=1)