Python如何遍历每一行并查看两列之间是否满足条件

Question

I have 3 columns. I want to update the third column, status , if the first column, a is greater than or equal to column b + 0.50. I've tried this following code but cannot get it to work:

if df['a'] >= (df['b'] + 0.50):
    df['status'] = 1

status is already populated with zeros.

how would i go about this?

Answer 1

You can try with np.where

df['status'] = np.where(df['a'] >= (df['b'] + 0.50),1,0)

Or just

df['status'] = (df['a'] >= (df['b'] + 0.50)).astype(int)

Or loc

df.loc[(df['a'] >= (df['b'] + 0.50)),'status'] = 1

Answer 2

You can use lambda function :

def myFunc(x): 
    if(x[0]>=x[1]+0.50) :
        return 1
    else: return x[2]

df['status'] = df.apply(lambda x:myFunc(x),axis=1)