How to retain column headers of data frame after Pre-processing in scikit-learn

Question

I have a pandas data frame which has some rows and columns. Each column has a header. Now as long as I keep doing data manipulation operations in pandas, my variable headers

Answer 1

According to Ami Tavory's reply here, per documentation, Imputer omits empty columns or rows (however you run it).
Thus, before running the Imputer and setting the column names as described above, run something like this (for columns):

X_train=X_train.dropna(axis=1, how='all')

df.dropna described here.