Another example of a lambdas that changes all values

simple_lambdas_example.py

# replace all values with the same thing
df[col1] = df[col1].apply(lambda x: x.replace(year=2109, month=1, day=1))
print(df[col1].head(2))

# output

"""
event_date
2109-01-01
2109-01-01
...
"""