Example 1: f string in python
name = "John Smith"
print(f"Hello, {name}")
name = "John Smith"
print("Hello, {}".format(name))
Example 2: python f-strings
>>> name = "Fred"
>>> f"He said his name is {name!r}."
"He said his name is 'Fred'."
>>> f"He said his name is {repr(name)}."
"He said his name is 'Fred'."
>>> width = 10
>>> precision = 4
>>> value = decimal.Decimal("12.34567")
>>> f"result: {value:{width}.{precision}}"
'result: 12.35'
>>> today = datetime(year=2017, month=1, day=27)
>>> f"{today:%B %d, %Y}"
'January 27, 2017'
>>> f"{today=:%B %d, %Y}"
'today=January 27, 2017'
>>> number = 1024
>>> f"{number:#0x}"
'0x400'
>>> foo = "bar"
>>> f"{ foo = }"
" foo = 'bar'"
>>> line = "The mill's closed"
>>> f"{line = }"
'line = "The mill\'s closed"'
>>> f"{line = :20}"
"line = The mill's closed "
>>> f"{line = !r:20}"
'line = "The mill\'s closed" '
Example 3: python f string
>>> name = "Eric"
>>> age = 74
>>> f"Hello, {name}. You are {age}."
'Hello, Eric. You are 74.'
Example 4: python f string
import math
print('[[fill]align] | f\'{"text":10}\' | ', f'{"text":10}')
print('[[fill]align] | f\'{"text":>10}\' | ', f'{"text":>10}')
print('[[fill]align] | f\'{"text":^10}\' | ', f'{"text":^10}')
print('[[fill]align] | f\'{"text":#>10}\' | ', f'{"text":#>10}')
print('[[fill]align] | f\'{"text":#<10}\' | ', f'{"text":#<10}')
print('[[fill]align] | f\'{"text":#^10}\' | ', f'{"text":#^10}')
print('[[fill]align] with numbers | f\'{12345:0=10}\' | ', f'{12345:0=10}')
print('[[fill]align] with numbers | f\'{-12345:0=10}\' | ', f'{-12345:0=10}')
print('[[fill]align] with numbers | f\'{12345:010}\' | ', f'{12345:010}')
print('[[fill]align] with numbers | f\'{-12345:010}\' | ', f'{-12345:010}')
print('[.precision] | f\'{math.pi:.2f}\' | ', f'{math.pi:.2f}')
print('[grouping_option] | f\'{1000000:,.2f}\' | ', f'{1000000:,.2f}')
print('[grouping_option] | f\'{1000000:_.2f}\' | ', f'{1000000:_.2f}')
print('[sign] (+/-) | f\'{12345:+}\' | ', f'{12345:+}')
print('[sign] (+/-) | f\'{-12345:+}\' | ', f'{-12345:+}')
print('[sign] (+/-) | f\'{12345:+10}\' | ', f'{12345:+10}')
print('[sign] (+/-) | f\'{-12345:+10}\' | ', f'{-12345:+10}')
print('[sign] (+/-) | f\'{12345:+010}\' | ', f'{12345:+010}')
print('[sign] (+/-) | f\'{-12345:+010}\' | ', f'{-12345:+010}')
print('[b] (binary) | f\'{10:b}\' | ', f'{10:b}')
print('[o] (octal) | f\'{10:o}\' | ', f'{10:o}')
print('[x] (hexadecimal) | f\'{100:x}\' | ', f'{100:x}')
print('[#b] (with notation base) | f\'{10:#b}\' | ', f'{10:#b}')
print('[#0] (with notation base) | f\'{10:#o}\' | ', f'{10:#o}')
print('[#x] (with notation base) | f\'{10:#x}\' | ', f'{10:#x}')
print('[e] (scientific notation) | f\'{345600000000:e}\' | ', f'{345600000000:e}')
print('[c] (character type) | f\'{65:c}\' | ', f'{65:c}')
print('percentage (multiply by 100) | f\'{0.25:0%}\' | ', f'{0.25:0%}')
print('percentage (multiply by 100) | f\'{0.25:.0%}\' | ', f'{0.25:.0%}')