Adding a currency symbol to polars dataframe values

When your dataframe contains monetary values such as budgets it’s helpful to include a currency symbol. This ensures your audience clearly understands whether the figures are in dollars, euros, pounds, or another currency.

Below is an example of a dataframe that displays budget figures for each department at Duwata Company.

shape: (5, 2)

Department	Budget
str	i64
"Hospitality"	50000
"Legal"	120000
"Finance"	80000
"Advertising"	60000
"Sales"	90000

Add currency to budget figures

If you were presenting these values to the American division of Duwata, you might want to include the dollar symbol in the Budget column values.

Here’s how you can do that using Polars.

(df
 .select('Department','Budget')
 .with_columns(Budget=pl.format("${}", pl.col("Budget")))
 )

shape: (5, 2)

Department	Budget
str	str
"Hospitality"	"$50000"
"Legal"	"$120000"
"Finance"	"$80000"
"Advertising"	"$60000"
"Sales"	"$90000"

If you were presenting the data to Duwata’s European division and wanted to use the euro symbol instead, you would simply replace $ with €.

(df
 .select('Department','Budget')
 .with_columns(Budget=pl.format("€{}", pl.col("Budget")))
 )

shape: (5, 2)

Department	Budget
str	str
"Hospitality"	"€50000"
"Legal"	"€120000"
"Finance"	"€80000"
"Advertising"	"€60000"
"Sales"	"€90000"

Note

Adding a currency symbol to the values in the Budget column converts the data type from numeric to string. As a result, you can no longer perform numeric operations like division on this column. This formatting change is meant purely for presentation purposes, such as displaying the data in a PowerPoint slide or a PDF document.

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