I have 4 columns (stimA_pos, stimB_pos, stimC_pos, stimD_pos) of strings defining the positions of images (left, right, up, down). Another column shows the string of the chosen image (decision_resp). I would like to create a new column showing the chosen image instead of 'left', 'right, etc. This should be the result (decision_resp_img):

Thanks for any help!

CodePudding user response：

df1.join(df1.reset_index().
 melt(['index' ,'decision_resp'], var_name = 'decision_resp_img').
 query('decision_resp == value').set_index('index')['decision_resp_img'].
 str.replace('_pos', ''))

  stimA_pos stimB_pos stimC_pos stimD_pos decision_resp decision_resp_img
0        up      left      down     right          left             stimB
1      down        up     right      left          down             stimA
2      left      down     right        up         right             stimC
3     right      left        up      down          down             stimD

CodePudding user response：

df["decision_resp_img"] = df.apply(lambda x: dict(zip((a:=dict(x[["stimA_pos","stimB_pos","stimC_pos","stimD_pos"]])).values(), a.keys()))[x["decision_resp"]].replace("_pos","") , axis=1)
df

output:

    stimA_pos   stimB_pos   stimC_pos   stimD_pos   decision_resp   decision_resp_img
0   up  left    down    right   left    stimB
1   down    up  right   left    down    stimA
2   left    down    right   up  right   stimC
3   right   left    up  down    down    stimD