String formatting

Variables and strings can be combined, using f-strings. f-strings contain placeholders with variable names and format characters. Here are some examples:

name = 'Roger'
number = 42
pi = 3.14159

print(f'Hello {name}')
print(f'Result: {number:6d}')
print(f'{number:06d}')
print(f'{name:>20} {name:20}')
print(f'{pi:8.3f})

The winged brackets are placeholders for the parameters in the format function. Thy consist of two parts {a:b}. Part a is a variable name (or expression). The optional part b contains format characters. Options include:

• {var} – insert the variable only.

• {var:xd} – an integer with x digits.

• {var:<xd} – a left-formatted integer with x digits.

• {var:0xd} – a left-formatted integer with x digits filled up with zeroes.

• {:>5} – a right-aligned string of width 5.

• {:6.2f} – a float number with 6 digits (2 after the dot).

Remark

The older method .format() (prior to Python 3.6) is sometimes used for string formatting:

print('{:6.3f}/{:6.3f}'.format(a, b))