python - Initialize dataframe with a constant -


initializing dataframe constant value not work,

pd.dataframe(0, index=[1,2,3])      # doesnt work!     # or pd.dataframe(0)                     # doesnt work! 

whereas observe that

(1) initializing series constant value works

pd.series(0, index=[1,2,3])         # works fine! 

(2) initializing dataframe none works

pd.dataframe(none, index=[1,2,3])   # works fine! 

(3) initializing dataframe when index , columns not provided works

pd.dataframe([1, 2, 3])             # works fine! pd.dataframe([0])                   # works fine! 

does know why?

i keen know more design consideration, rather answer "if check pandas code, you'd see fails 1 of checks data dimension expected >1.. blah blah".

i think should work intuitively (considering pandas intelligent in assigning default col , index when not provided, , guesses dimensions data given).

may there reason behaviour can't figure.

a pd.dataframe 2-dimensional. when specify

pd.dataframe(0, index=[1, 2, 3]) 

you telling constructor assign 0 every row indices 1, 2, , 3. columns? didn't define columns.

you can 2 things

option 1
specify columns

pd.dataframe(0, index=[1, 2, 3], columns=['x', 'y'])     x  y 1  0  0 2  0  0 3  0  0 

option 2
pass list of values

pd.dataframe([[0]], index=[1, 2, 3])     0 1  0 2  0 3  0 

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