Slightly more compact:
df = pd.DataFrame([1, 2, 3, 4, 5], index=[100, 29, 234, 1, 150], columns=['A'])
df = df.sort_index()
print(df)
Note:
sort has been deprecated, replaced by sort_index for this scenarioinplace as it is usually harder to read and prevents chaining. See explanation in answer here:
Pandas: peculiar performance drop for inplace rename after dropna