Formatting output with f-strings

f-strings (spec 8.2.2)

Put f before the quotes and expressions inside braces. After a colon, a format specifier controls the layout: {value:align width .precision type}.

name = "Ana"
score = 7.456
print(f"{name} scored {score:.2f}")
print(f"{name:<8}|{name:>8}|{name:^8}|")
print(f"{42:5d}|{42:<5d}|{3.14159:8.3f}|")
print(f"{5:+d} {-5:+d}")

Output:

Ana scored 7.46
Ana     |     Ana|  Ana   |
   42|42   |   3.142|
+5 -5

The parts of a format specifier

Tables of output

Use the same widths for headings and data so the columns line up:

data = [["Pen", 3, 0.5], ["Notebook", 12, 2.25]]
print(f"{'Item':<10}{'Qty':^5}{'Price':>8}")
for item in data:
    print(f"{item[0]:<10}{item[1]:^5d}{item[2]:>8.2f}")

Output:

Item       Qty    Price
Pen         3      0.50
Notebook   12      2.25

The sample paper awarded marks for headings, centre-aligned text and integers and right-aligned real numbers.

format() and str()

"{:>6.1f}".format(x) uses the same specifiers. Joining with str() and + also works, but you then control spacing yourself.

Worked example

Display the price 4.5 right-aligned in a width of 8 with 2 decimal places, preceded by the label 'Total:'.

1. The specifier is :>8.2f
2. f"Total:{4.5:>8.2f}"
3. Output: Total:····4.50

Answer: Total:····4.50 (each · is a space)

Check yourself

1. What is displayed when this code runs? ```python print(f"{2/3:.3f}") ```
   Show answer

   0.667. 2/3 = 0.6666..., shown to 3 decimal places: 0.667.

2. How many characters long is the string produced by f"{'cat':>7}"?
   Show answer

   7. The width of 7 pads 'cat' with 4 spaces on the left, making 7 characters.

3. What is displayed when this code runs? ```python print(f"[{'ab':<sup>6</sup>}]") ```
   • ``` [ab ] ```
   • ``` [ ab] ```
   • ``` [ ab ] ```
   • ``` [ab] ```
   Show answer

   ``` [ ab ] ```. ^ centres the text in a width of 6: two spaces each side: ``` [ ab ] ```

4. What is displayed when this code runs? ```python print(f"{7:+d}|{-7:+d}") ```
   • 7|-7
   • +7|-7
   • +7|+7
   • +7|7
   Show answer

   +7|-7. The + sign option always shows the sign: +7|-7.

5. What is displayed when this code runs? ```python print(f"{3.0:.0f}|{17:04d}") ```
   • 3.0|17
   • 3|17
   • 3.|0017
   • 3|0017
   Show answer

   3|0017. .0f shows no decimal places, and 04d pads the integer with zeros to width 4: 3|0017.

6. This line should display a mark such as 67.5 right-aligned in 6 characters with 1 decimal place, between bars. Which line completes it? ```python mark = 67.5 __________ ```
   • `print(f"|{mark:<6.1f}|")`
   • `print(f"|{mark:>6.1f}|")`
   • `print(f"|{mark:>1.6f}|")`
   • `print(f"|{mark:6d}|")`
   Show answer

   `print(f"|{mark:>6.1f}|")`. > right-aligns, 6 is the width and .1f gives 1 decimal place.

7. Without an alignment symbol, how are numbers and strings aligned in a wider field?
   • Numbers left, strings right
   • Centred, whatever the type
   • Left, whatever the type
   • Numbers right, strings left
   Show answer

   Numbers right, strings left. The defaults are right alignment for numbers and left alignment for text.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Computer Science specification (XCP01/YCP01), first teaching 2026
• Pearson IAL Computer Science Unit 2 Programming Language Subset (PLS), Python 3
• Pearson IAL Computer Science IAS sample assessment materials (Unit 2 paper and mark scheme)

Last updated 8 November 2026. Spotted a mistake? Tell us.