regex101: Python Match Workspace

Pro

^start of line

Comment: (?P<Sign>[-+]*)

Group Prefix(?P<Prefix> # prefix can be 0(b+|B+|x+|X+)? # 0, 0b, 0B, 0x, 0X, 0bb, 0BB, ... | # or empty )

1st Alternative # prefix can be 0(b+|B+|x+|X+)? # 0, 0b, 0B, 0x, 0X, 0bb, 0BB, ...

Comment: prefix can be

0the literal text 0

Group 2(b+|B+|x+|X+)?

?repeats the group contents below at most once:

1st Alternativeb+

b+the literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive), repeated at least once

2nd AlternativeB+

B+the literal B (66₁₀ / 102₈ / 42₁₆) (case sensitive), repeated at least once

3rd Alternativex+

x+the literal x (120₁₀ / 170₈ / 78₁₆) (case sensitive), repeated at least once

4th AlternativeX+

X+the literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive), repeated at least once

Comment: 0, 0b, 0B, 0x, 0X, 0bb, 0BB, ...

2nd Alternative # or empty

Comment: or empty

Group Constant(?P<Constant> # BUG If prefix is followed by two or more x, it doesn't works correctly (?<=0[xX]) # is prefix for hex digits? [\da-fA-F]+ # so, collect hex digits | # otherwise \d+ # collect decimal digits )

1st Alternative # BUG If prefix is followed by two or more x, it doesn't works correctly (?<=0[xX]) # is prefix for hex digits? [\da-fA-F]+ # so, collect hex digits

Comment: BUG If prefix is followed by two or more x, it doesn't works correctly

Positive Lookbehind(?<=0[xX])

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[xX]

xthe literal x (120₁₀ / 170₈ / 78₁₆) (case sensitive)

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

Comment: is prefix for hex digits?

Character Class[\da-fA-F]+

+matches at least one character from the set below:

\da Unicode decimal digit

a-fone character from a (97₁₀) to f (102₁₀) (case sensitive)

A-Fone character from A (65₁₀) to F (70₁₀) (case sensitive)

Comment: so, collect hex digits

2nd Alternative # otherwise \d+ # collect decimal digits

Comment: otherwise

\d+a Unicode decimal digit, repeated at least once

Comment: collect decimal digits

Group Suffix(?P<Suffix> (?<=[eE]) # is constant ending with an `E`? [\w\d+\-.]* # so, collect `+` and `-` operators | # otherwise \w # collect suffixes that starts with an letter [\w\d.]* # and letters, digits and dots that follows it | # finally, do suffix be optional (empty) )

1st Alternative (?<=[eE]) # is constant ending with an `E`? [\w\d+\-.]* # so, collect `+` and `-` operators

Positive Lookbehind(?<=[eE])

Character Class[eE]

ethe literal e (101₁₀ / 145₈ / 65₁₆) (case sensitive)

Ethe literal E (69₁₀ / 105₈ / 45₁₆) (case sensitive)

Comment: is constant ending with an `E`?

Character Class[\w\d+\-.]*

*matches any number of characters from the set below:

\wa Unicode word character

\da Unicode decimal digit

+the literal + (43₁₀ / 53₈ / 2B₁₆)

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

Comment: so, collect `+` and `-` operators

2nd Alternative # otherwise \w # collect suffixes that starts with an letter [\w\d.]* # and letters, digits and dots that follows it

Comment: otherwise

\wa Unicode word character

Comment: collect suffixes that starts with an letter

Character Class[\w\d.]*

*matches any number of characters from the set below:

\wa Unicode word character

\da Unicode decimal digit

.the literal . (46₁₀ / 56₈ / 2E₁₆)

Comment: and letters, digits and dots that follows it

3rd Alternative # finally, do suffix be optional (empty)

Comment: finally, do suffix be optional (empty)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

25 tokens

Regular Expression

^
# (?P<Sign>[-+]*)
(?P<Prefix>         # prefix can be
    0(b+|B+|x+|X+)? #   0, 0b, 0B, 0x, 0X, 0bb, 0BB, ...
    |               # or empty
)
(?P<Constant>
    # BUG If prefix is followed by two or more x, it doesn't works correctly
    (?<=0[xX])       # is prefix for hex digits?
        [\da-fA-F]+  #   so, collect hex digits
    |                # otherwise
    \d+              #   collect decimal digits
)
(?P<Suffix>
    (?<=[eE])        # is constant ending with an `E`?
        [\w\d+\-.]*  #   so, collect `+` and `-` operators
    |                # otherwise
        \w           #   collect suffixes that starts with an letter
        [\w\d.]*     #     and letters, digits and dots that follows it
    |                # finally, do suffix be optional (empty)
)

0xc0ffee
0xb0b

Extraction

0xc0ffee
0xb0b