1 >>> print('{0:b}'.format(3))
 2 11
 3 >>> print('{:c}'.format(20))
 4
 5 >>> print('{:d}'.format(20))
 6 20
 7 >>> print('{:o}'.format(20))
 8 24
 9 >>> print('{:x}'.format(20))
10 14
11 >>> print('{:e}'.format(20))
12 2.000000e+01
13 >>> print('{:g}'.format(20.1))
14 20.1
15 >>> print('{:f}'.format(20))
16 20.000000
17 >>> print('{:n}'.format(20))
18 20
19 >>> print('{:%}'.format(20))
20 2000.000000%

1 >>> # format also supports binary numbers
2 >>> "int: {0:d};  hex: {0:x};  oct: {0:o};  bin: {0:b}".format(42)
3 'int: 42;  hex: 2a;  oct: 52;  bin: 101010'
4 >>> # with 0x, 0o, or 0b as prefix:
5 >>> "int: {0:d};  hex: {0:#x};  oct: {0:#o};  bin: {0:#b}".format(42)  # 在前面加“#”，则带进制前缀
6 'int: 42;  hex: 0x2a;  oct: 0o52;  bin: 0b101010'

 1 >>> print('{} and {}'.format('hello','world'))  # 默认左对齐
 2 hello and world
 3 >>> print('{:10s} and {:>10s}'.format('hello','world'))  # 取10位左对齐，取10位右对齐
 4 hello      and      world
 5 >>> print('{:^10s} and {:^10s}'.format('hello','world'))  # 取10位中间对齐
 6   hello    and   world
 7 >>> print('{} is {:.2f}'.format(1.123,1.123))  # 取2位小数
 8 1.123 is 1.12
 9 >>> print('{0} is {0:>10.2f}'.format(1.123))  # 取2位小数，右对齐，取10位
10 1.123 is       1.12
11
12 >>> '{:<30}'.format('left aligned')  # 左对齐
13 'left aligned                  '
14 >>> '{:>30}'.format('right aligned')  # 右对齐
15 '                 right aligned'
16 >>> '{:^30}'.format('centered')  # 中间对齐
17 '           centered           '
18 >>> '{:*^30}'.format('centered')  # 使用“*”填充
19 '***********centered***********'
20 >>>'{:0=30}'.format(11)  # 还有“=”只能应用于数字，这种方法可用“>”代替
21 '000000000000000000000000000011'

1 >>> '{:+f}; {:+f}'.format(3.14, -3.14)  # 总是显示符号
2 '+3.140000; -3.140000'
3 >>> '{: f}; {: f}'.format(3.14, -3.14)  # 若是+数，则在前面留空格
4 ' 3.140000; -3.140000'
5 >>> '{:-f}; {:-f}'.format(3.14, -3.14)  # -数时显示-，与'{:f}; {:f}'一致
6 '3.140000; -3.140000'

1 >>> points = 19
2 >>> total = 22
3 >>> 'Correct answers: {:.2%}'.format(points/total)
4 'Correct answers: 86.36%'

1 >>> import datetime
2 >>> d = datetime.datetime(2010, 7, 4, 12, 15, 58)
3 >>> '{:%Y-%m-%d %H:%M:%S}'.format(d)
4 '2010-07-04 12:15:58'

1 >>> '{:,}'.format(1234567890)
2 '1,234,567,890'

 1 >>> for align, text in zip('<^>', ['left', 'center', 'right']):
 2 ...     '{0:{fill}{align}16}'.format(text, fill=align, align=align)
 3 ...
 4 'left<<<<<<<<<<<<'
 5 '^^^^^center^^^^^'
 6 >>>>>>>>>>>right'
 7 >>>
 8 >>> octets = [192, 168, 0, 1]
 9 >>> '{:02X}{:02X}{:02X}{:02X}'.format(*octets)
10 'C0A80001'
11 >>> int(_, 16)  # 官方文档给出来的，无法在IDLE复现
12 3232235521
13 >>>
14 >>> width = 5
15 >>> for num in range(5,12):
16 ...     for base in 'dXob':
17 ...         print('{0:{width}{base}}'.format(num, base=base, width=width), end=' ')
18 ...     print()
19 ...
20     5     5     5   101
21     6     6     6   110
22     7     7     7   111
23     8     8    10  1000
24     9     9    11  1001
25    10     A    12  1010
26    11     B    13  1011

1 """
2 replacement_field ::= "{" [field_name] ["!" conversion] [":" format_spec] "}"
3 conversion ::= "r" | "s" | "a"
4 这里只有三个转换符号，用"!"开头。
5 "!r"对应 repr()；"!s"对应 str(); "!a"对应ascii()。
6 """
7
8 >>> "repr() shows quotes: {!r}; str() doesn't: {!s}".format('test1', 'test2')
9 "repr() shows quotes: 'test1'; str() doesn't: test2"  # 输出结果是一个带引号，一个不带

 1 # a.format(b)
 2 >>> "{0} {1}".format("hello","world")
 3 'hello world'
 4
 5
 6 # f"xxxx"
 7 # 可在字符串前加f以达到格式化的目的，在{}里加入对象，此为format的另一种形式：
 8
 9 >>> a = "hello"
10 >>> b = "world"
11 >>> f"{a} {b}"
12 'hello world'
13
14
15
16 name = 'jack'
17 age = 18
18 sex = 'man'
19 job = "IT"
20 salary = 9999.99
21
22 print(f'my name is {name.capitalize()}.')
23 print(f'I am {age:*^10} years old.')
24 print(f'I am a {sex}')
25 print(f'My salary is {salary:10.3f}')
26
27 # 结果
28 my name is Jack.
29 I am ****18**** years old.
30 I am a man
31 My salary is   9999.990