String formatting.

String formatting

There are two ways to format a Python string: a percent-semicolon, format-mode

When formatting a string, Python uses a string as a template. There are formatting characters in the template that reserve locations for real values and describe the format in which real values should be rendered. Python uses a tuple to pass multiple values to the template, each of which corresponds to a format character.

Percent-Semicolon mode:

The format can be further controlled in the following ways

%[(name)][flags][width]. [Precision]typecode (name) for name flags can have +,-, ' or 0. + Indicates right alignment. -Indicates left alignment. ' is a space that fills a space on the left side of a positive number to align with a negative number. 0 means using 0 padding. Width indicates the display width precision indicates the precision after the decimal point

[]: Indicates an optional

fill: Optional, white space filled characters

align: optional, on its way (should be used with width)

• <, content left justified
• Content right-aligned (default)
• =, the content is right-aligned, the symbol is placed to the left of the padding character, and only valid for numeric types. Even: symbol + filler + number
• ^, content centered

sign: optional, with unsigned digits

• +, positive home Plus, minus plus negative;
• -The plus sign does not change, minus is negative;
• Spaces, plus spaces, minus signs and negative;

#: Optional, for binary, octal, hex, if Add #, will show 0b/0o/ox, otherwise not display

,: Optional, add separators for numbers, such as: 1,000,000

width: Optional, the format of the occupied position

. Precision: Optional, decimal retention accuracy

Type: Optional, formatted type

• passed arguments for string type
  • • s, format string type data
    • blank, unspecified Type, the default is None, with the S
• passed in an integer type parameter
  • • B, convert the 10 binary integers automatically to a 2 binary representation and then format
    • C, automatically converts a 10-based integer to its corresponding Unicode character
    • d, decimal integer
    • O, the 10 binary integers are automatically converted to 8 binary representations and then formatted;
    • x, automatically converts a 10-based integer to a 16-binary representation and then formats (lowercase x)
    • X, automatically converts a 10-based integer to a 16-binary representation and then formats (uppercase X)
• incoming float or decimal type   parameter
• E, converted to scientific notation (lowercase e), then formatted;
• E, converted to scientific notation (capital E) after formatting;
• F, converted to floating point (6 bits left after the default decimal point), and then formatted;
• F, converted to floating point (6 bits left after the default decimal point), and then formatted;
• g, automatically toggle between E and F
• G, automatically toggle between E and F
• %, display percent (the default is 6 digits after the decimal)

s = ' I am%s,age%d '% (' kai ', +) print (s) execution result: I am kai,age 19s = ' I am% (N1) S,age% (N2) s '% {' N1 ': ' Kai ', ' N2 ': ' + '}print (s ) Execution result: I am kai,age 100s = ' percent%.2f '% 1.2222print (s) execution result: percent 1.22s = ' I am% (ZZ). 2f '%{' zz ': 3.555555}print (s) execution result: I am 3.56s = ' I am% (kai). 2f%%{' kai ': 2.55555}print (s) execution result: I am 2.56

String formatting.