Get first element of Series without knowing the index [duplicate]

Question

Is that any way that I can get first element of Seires without have information on index.

For example,We have a Series

    import pandas as pd     key='MCS096'     SUBJECTS=pd.DataFrame({'ID':Series([146],index=[145]),\                    'study':Series(['MCS'],index=[145]),\                    'center':Series(['Mag'],index=[145]),\                    'initials':Series(['MCS096'],index=[145])                    }) 

prints out SUBJECTS:

    print (SUBJECTS[SUBJECTS.initials==key]['ID'])     145    146     Name: ID, dtype: int64 

How can I get the value here 146 without using index 145?

Thank you very much

Answer 1

Use iloc to access by position (rather than label):

In [11]: df = pd.DataFrame([[1, 2], [3, 4]], ['a', 'b'], ['A', 'B'])  In [12]: df Out[12]:     A  B a  1  2 b  3  4  In [13]: df.iloc[0]  # first row in a DataFrame Out[13]:  A    1 B    2 Name: a, dtype: int64  In [14]: df['A'].iloc[0]  # first item in a Series (Column) Out[14]: 1