["python","pandas"]
Set value for particular cell in pandas DataFrame with iloc

I have a question similar to this and this. The difference is that I have to select row by position, as I do not know the index. I want to do something like df.iloc[0, 'COL_NAME'] = x, but iloc does not allow this kind of access. If I do df.iloc[0]['COL_NAME'] = x the warning about chained indexing appears.
For mixed position and index, use .ix. BUT you need to make sure that your index is not of integer, otherwise it will cause confusions. df.ix[0, 'COL_NAME'] = x Update: Alternatively, try df.iloc[0, df.columns.get_loc('COL_NAME')] = x Example: import pandas as pd import numpy as np # your data # ======================== np.random.seed(0) df = pd.DataFrame(np.random.randn(10, 2), columns=['col1', 'col2'], index=np.random.randint(1,100,10)).sort_index() print(df) col1 col2 10 1.7641 0.4002 24 0.1440 1.4543 29 0.3131 -0.8541 32 0.9501 -0.1514 33 1.8676 -0.9773 36 0.7610 0.1217 56 1.4941 -0.2052 58 0.9787 2.2409 75 -0.1032 0.4106 76 0.4439 0.3337 # .iloc with get_loc # =================================== df.iloc[0, df.columns.get_loc('col2')] = 100 df col1 col2 10 1.7641 100.0000 24 0.1440 1.4543 29 0.3131 -0.8541 32 0.9501 -0.1514 33 1.8676 -0.9773 36 0.7610 0.1217 56 1.4941 -0.2052 58 0.9787 2.2409 75 -0.1032 0.4106 76 0.4439 0.3337