# numpy find columns containing nan

# in each case returns array of bool np.isnan(a).any(axis=0) # columns where any value is nan np.isnan(a).all(axis=0) # columns where all values are nan

**Here is what the above code is Doing:**

1. np.isnan(a) returns a boolean array of the same shape as a, where True indicates a value is nan.

2. np.isnan(a).any(axis=0) returns a boolean array of the same shape as a, where True indicates that any value in the column is nan.

3. np.isnan(a).all(axis=0) returns a boolean array of the same shape as a, where True indicates that all values in the column are nan.