count na column wise code example

Example 1: how to count the number of NA in r

sum(is.na(df$col))

Example 2: find the number of nan per column pandas

In [1]: s = pd.Series([1,2,3, np.nan, np.nan])

In [4]: s.isna().sum()   # or s.isnull().sum() for older pandas versions
Out[4]: 2