Python string formatting% with format () function IX

This is the content of the December plan, beginning in January 2018 ~

If there is any mistake, please ask for it ~

Formatting this has been mentioned in print a little bit, and the truth is very similar to the C language.

% of the method:

%[(name)][flags][width]. [Precision]typecode

• (name)       optional, to select the specified key ,

     Print (" Year:% ( Year) S "%{' (Year ': 2018})   

• flags           optional, available values are:
  • em>+       Right, positive plus, negative before plus minus;
  • -        left-aligned, positive unsigned before negative, plus minus sign;
  • spaces     Right alignment, positive numbers with spaces, negative numbers before plus minus;
  • 0         right-aligned; no sign before positive, negative minus with 0 padding
• width         optional, occupy width
• . Precision   Optional, number of digits left after decimal point
• typecode     required (this should have been seen)

% c	Convert to character (ASCII value, or string of length one)
%r	Prioritize string conversions with the repr () function
%s	Prioritize string conversions with the str () function
%d/%i	Turn signed decimal number
%u	Turn unsigned decimal number
%o	To unsigned octal number
%x /%x	Turns to unsigned hexadecimal number (x/x for the case of converted hexadecimal characters)
%e/%e	Turn scientific notation (e/e control output e/e)
%f/%f	Turns into floating-point numbers (fractional parts are naturally truncated)
%g/%g	%e and%f/%e and%f abbreviations
%	Output% (the format string includes a percent semicolon, so you must use a percentile)

%r and%s are string conversions, so what's the difference?

1String ="hello\tworld\n"2 Print("%s"%string)3 Print("%r"%string)4 the string received by Hello World Str () is user-oriented5 6 'hello\tworld\n'Repr () The resulting string is machine-oriented

And most of the other symbols have been seen, here no longer explain

The Str.format () function replaces the previous "%" with "{}" and ":". Symbol.

[[Fill]align] [Sign] [#] [0] [Width] [,] [. Precision] [Type]

{} by location matching parameters, of course, do not write the default order, you can repeatedly appear
* What does "abc" mean to the function to speak, which is understood here as "abc" = ' A ', ' B ', ' C ' becomes

 1  print  (  " {1},{0},{2}  . Format (*"   ABC     print  ( " {1},{2},{0}  . Format ("   A  ,    b  ,    C   )) 

B,a,cb,c,a

{}  Configuring parameters by name

1 Print ("{a},{b},{c}". Format (a=1,b='s', c=4))

1,s,4

{} configure parameters by subscript

 1  alist=[ " s   ", 2,"  c   "    print  ( " {0[1]}  . Format (alist) 

alist=['s', 2,'C']print('{ 0[1]}'. Format (alist)#2

The above is also known as mapping list and dict

The next step is a series of {: XXXXXX} operations.

Python string formatting% with format () function IX