Easily convert text to date values in polars

to_date

Usually, when you want to convert string (text) data to a date type, you have to introduce some esoteric formatting like “%m%d%Y”. Unfortunately, this looks like gibberish to most people. The good news is that in Polars, you don’t always need to know that strange formatting, especially when your data starts with the year.

Below is a dataframe showing date values stored as text.

shape: (4, 2)

Itinerary	Date
str	str
"Los Angeles"	"2025-05-01"
"Syndney"	"2025-05-15"
"Wellington"	"2025-06-02"
"Tokio"	"2025-06-17"

Convert text to date

Since the values in Date start with the year, then month, and day, you can use the Polars expression to_date to convert the data type from text to date, like this:

(df
 .with_columns(pl.col('Date').str.to_date())
 )

shape: (4, 2)

Itinerary	Date
str	date
"Los Angeles"	2025-05-01
"Syndney"	2025-05-15
"Wellington"	2025-06-02
"Tokio"	2025-06-17

Now the data type in Date has been successfully changed from text to date.

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