df = df.astype({'N_BEDROOM': 'object', 'N_ROOM': 'object', 'N_BATHROOM': 'object'}) code example

Example 1: convert a pandas column to int

# convert Series
my_series = pd.to_numeric(my_series)

# convert column "a" of a DataFrame
df["a"] = pd.to_numeric(df["a"])

Example 2: set type of column pandas

df.astype(int)