import pandas as pd
from pandas.api.types import is_string_dtype


print(f"pandas {pd.__version__}")

names = pd.Series(["Ada", "Lin", None], name="name")
mixed_probe = pd.Series(["Ada", 2.5], dtype="object", name="mixed")

print(f"inferred dtype: {names.dtype}")
print(f"object dtype check: {names.dtype == 'object'}")
print(f"string column check: {is_string_dtype(names)}")
print(f"mixed object check: {is_string_dtype(mixed_probe)}")
print(f"missing value is None: {names.iloc[2] is None}")
print(f"missing value is NA: {pd.isna(names.iloc[2])}")
print(f"str accessor result: {names.str.upper().tolist()}")

try:
    names.iloc[1] = 2.5
except TypeError as exc:
    print(f"non-string write: {exc}")

mixed = names.astype("object")
mixed.iloc[1] = 2.5
print(f"mixed opt-out dtype: {mixed.dtype}")
print(f"mixed opt-out value: {mixed.iloc[1]}")
print(f"values object: {type(names.values).__name__}")
print(f"numpy object: {type(names.to_numpy()).__name__}")