python：dataframe 列迭代在第一轮后停止

Question

I am trying to print the index where 1 is contained in a specific column of a dataframe. The for loop meets the condition at the first iteration and goes back to it instead of moving forward. I have looked all over and have found others with the same problem, however, I still cannot figure out the solution.

import pandas as pd
d = {'a': [0.1, 0.2,0.3,0.4,0.5,0.6], 'b': [0.6, 0.8,0.3,0.4,0.1,0.1],
     'c': [0.7, 0.3,0.9,0.4,1.0,0.2],'d': [1,0,0,1,0,1]}
df = pd.DataFrame(data=d)
klist=[]
for i in (df.d):
    if  i == 1:
        klist.append(df.d.tolist().index(i))
           
print(klist) # should print [0, 3, 5] instead of [0, 0, 0]

Answer 1

Use indexing rather than a loop

klist = df[df['d'] == 1].index.tolist()
print(klist)

# Output:
[0, 3, 5]