Need to turn a task’s name and urgency into a readable line? An f-string places values directly in a string literal. Prefix the quoted string with `f`, then put each variable inside curly braces. Integers and other nonstring values are converted for output. section 2.1 section 2.1.2
Build a task label
```python name = "Homework" urgency = 5 label = f"Name: {name}; Urgency Level: {urgency}" print(label) # Name: Homework; Urgency Level: 5 ``` The braces mark the values to insert; the punctuation outside them stays as written. section 2.1 section 2.1.2
Braces can also contain an expression, such as `tasks[0]`, `task_name.title()`, or `number * number`. The expression is evaluated before its result appears in the string. Keep it short: if calculating a value inside the braces takes effort to read, give that value a descriptive variable first. section 2.1.3
Format values for display
```python name = "Laundry" urgency = 3 price = 130.675 print(f"{name:^12} {urgency:^12}") print(f"Price: {price:.2f}") # Laundry 3 # Price: 130.68 ``` A colon inside the braces starts an optional format specifier. Here `^12` centers a value in a field 12 characters wide, while `.2f` displays a number with two decimal places. section 2.1.4
Choose a specifier for the output you need:
- `<`, `>`, and `^` align text left, right, and center; a field can use spaces or a chosen padding character. section 2.1.4
- `,d` separates digits in a large integer; `.2f` sets two decimal places; `.2%` displays a percentage with two decimal places. section 2.1.4
- If several fields need the same specifier, store it once and use a nested field such as `f'{name:{fmt}}'` rather than repeating it. section 2.1.4
Print literal curly braces
To show braces around a formatted price, double the braces that should print literally: ```python product = {"name": "Vacuum", "price": 130.675} print(f"{product['name']}: {{{product['price']:.2f}}}") # Vacuum: {130.68} ``` section 2.1.6
Prefer f-strings when assembling readable output from related values. For a few plain strings, concatenation is also reasonable; when the strings are already in an iterable, consider `join` instead. section 2.1.5 section 2.3.4
Table 2.2 Common format specifiers for formatting numbers with f-strings (view table figure)
| Percentage with two-digit precision2 |
Compare common integer and floating-point format specifiers when choosing a numeric display. section 2.1.4
