将函数应用于熊猫中的不同列

Question

I have a puzzling case, my data frame look like this

  id    high low medium count
0  0     0    4    8     12
1  1     5    2    1      8

I want to generate 3 additional columns for each of the level: high, low medium.

I defined a function

def foo(row['high']):
    return  (1/3+row['high']/(1+row['count']))

I think I need to apply this function 3 times, and change the row['high'], row['low'] and row['medium'].

I've used something like

df = df.apply(foo,axis=1)

However, it doesn't work. I wonder if there is a good way (maybe I could just apply this function once?) to do this....

Answer 1

You can't define a function that has an indexed variable as a parameter name. Change this:

def foo(row['high']):

to this:

def foo(row):

But, for what you are doing, you don't need to apply a function. It can be accomplished with operations on the columns.

(1/3)+df['high']/(1+df['count'])

# returns:
0    0.333333
1    0.888889
dtype: float64