string Formatting
There are two ways to format a python string:% format character, format mode
% Format character
%[(name)][flags][width]. [Precision]typecode
- (name) optional, used to select the specified key
- Flags are optional, and the values to choose from are:
- + Right-aligned, positive plus, negative before plus minus;
- -left-justified; no sign before positive number, plus minus sign before negative number;
- Spaces are right-justified, plus a positive number before a negative number plus a minus sign;
- 0 Right alignment, no sign before positive number, minus sign before negative, and 0 padding in blank
- Width selectable, occupied widths
- . Precision optional, number of digits retained after the decimal point
- TypeCode must choose
- S, gets the return value of the __str__ method of the passed-in object and formats it to the specified location
- R, gets the return value of the __repr__ method of the passed-in object and formats it to the specified location
- C, Integer: Converts a number to its Unicode corresponding value, 10 binary range is 0 <= i <= 1114111 (py27 only supports 0-255); character: add character to specified position
- O, converts an integer to an octal representation and formats it to a specified location
- X, converts an integer to a hexadecimal representation and formats it to a specified location
- D, converts an integer, floating-point number to a decimal representation, and formats it to a specified position
- E, converting integers, floating-point numbers to scientific notation, and formatting them to a specified location (lowercase e)
- E, converting integers, floating-point numbers into scientific notation, and formatting them to a specified position (uppercase E)
- F, converts an integer, floating-point number to a floating-point number representation, and formats it to a specified position (the default is 6 digits after the decimal point)
- F, ibid.
- G, auto-adjust convert integers, floating-point numbers to floating-point or scientific notation (more than 6 digits in scientific notation), and format them to a specified location (if scientific counts are e;)
- G, auto-adjust convert integers, floating-point numbers to floating-point or scientific notation (more than 6 digits in scientific notation), and format them to a specified location (if scientific counts are e;)
- %, when there is a format flag in the string, a percent sign is required
Note: There is no way to automatically convert an integer to a binary representation in Python with a percent-semicolon format
(name) optional, used to select the specified key
""%{' name ': ' xx ', ' age ': 'print(a)
Execution Result:
XX-----20
Flags are optional, and the values to choose from are:
- + Right-aligned, positive plus, negative before plus minus;
- -left-justified; no sign before positive number, plus minus sign before negative number;
- Spaces are right-justified, plus a positive number before a negative number plus a minus sign;
- 0 Right alignment, no sign before positive number, minus sign before negative, and 0 padding in blank
Width selectable, occupied widths
Name 10-bit, +, right-aligned, age 10-bit,-, left-justified
" % (name) +10s ————————% (age) -10d ————————"%{'name':'xx 'age': 'print' (b)
Execution Result:
XX ———————— ————————
Spaces, right-aligned
0, fill the blanks with 0
""%{' Year ':, ' age ': -20} Print(c)
Execution Result:
. Precision optional, number of digits retained after the decimal point
Only two decimal places are reserved
' --------% (p). 2f'%{'P': 1.23456'--------% (P) F '%{'p': 1.23456}print(d) Print(D1)
Execution Result:
--------1.23--------1.234560
TypeCode must choose
- C, Integer: Converts a number to its Unicode corresponding value, 10 binary range is 0 <= i <= 1114111 (py27 only supports 0-255); character: add character to specified position
- O, converts an integer to an octal representation and formats it to a specified location
- X, converts an integer to a hexadecimal representation and formats it to a specified location
E ='***%c***%o***%x'% (65,15,15)print(e)
Execution Result:
A***17***f
- E, converting integers, floating-point numbers to scientific notation, and formatting them to a specified location (lowercase e)
- E, converting integers, floating-point numbers into scientific notation, and formatting them to a specified position (uppercase E)
' -----% (num) e------% (num) e'%{'num': 1000000000}Print (f)
Execution Result:
-----1.000000e+09------1.000000E+09
- G, auto-adjust convert integers, floating-point numbers to floating-point or scientific notation (more than 6 digits in scientific notation), and format them to a specified location (if scientific counts are e;)
- G, auto-adjust convert integers, floating-point numbers to floating-point or scientific notation (more than 6 digits in scientific notation), and format them to a specified location (if scientific counts are e;)
' -----% (num) g------% (NUM1) G'%{'num': 1000000000,'num1 ': ' + 'print(g)
Execution Result:
-----1e+09------100
- %, when there is a formatting flag in the string, a percent sign (similar to the turn effect) is required
' AAA% ' Print 'AAA%s percent'('bbb')print( S1)
Execution Result:
AAA%
format Mode
[[Fill]align] [Sign] [#] [0] [Width] [,] [. Precision] [Type]
- Fill "optional" white space filled with characters
- Align "optional" alignment (required 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 numbers
- +, 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 added #, 0b/0o/0x is displayed, otherwise not displayed
- , "optional" adds a delimiter to the number, such as: 1,000,000
- width "Optional" format the size of the placeholder
- . Precision "optional" decimal digits reserved Precision
- Type "optional" formatting types
- Parameters passed into the string type
- s, format string type data
- Blank, no type specified, default is None, same as S
- Parameters passed into the integer type
- B, automatic conversion of 10 binary integers to 2 binary representation and then formatting
- C, automatic conversion of 10 binary integers to their corresponding Unicode characters
- d, decimal integer
- O, the 10 binary integers are automatically converted to 8 binary representation and then formatted;
- X, automatically converts 10 binary integers to 16 binary representation and then formats (lowercase x)
- X, automatically converts 10 binary integers to 16 binary representation and then formats (uppercase X)
- Parameters passed in floating-point or decimal type
- E, converted to scientific notation (lowercase e), and then formatted;
- E, converted to scientific notation (capital E), and then formatted;
- F, converted to floating-point type (6 digits after the default decimal point), and then formatted;
- F, converted to floating-point type (6 digits after the default decimal point), and then formatted;
- G, automatically switch between E and F
- G, automatically switch between E and F
- %, display percent (default 6 digits after decimal)
Fill "optional" white space filled with characters
Align "optional" alignment (required 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
width "Optional" format the size of the placeholder
S1 ='---{:* ^20s}----'. Format ('Welcome')Print(s1) S2='---{:* >20s}----'. Format ('Welcome')Print(S2) S3='---{:* <20s}----'. Format ('Welcome')Print(S3)
Execution Result:
---******welcome*******-------*************welcome-------welcome*************----
# "optional" for binary, octal, hex, if added #, 0b/0o/0x is displayed, otherwise not displayed
- B, automatic conversion of 10 binary integers to 2 binary representation and then formatting
- C, automatic conversion of 10 binary integers to their corresponding Unicode characters
- d, decimal integer
- O, the 10 binary integers are automatically converted to 8 binary representation and then formatted;
- X, automatically converts 10 binary integers to 16 binary representation and then formats (lowercase x)
- X, automatically converts 10 binary integers to 16 binary representation and then formats (uppercase X)
Three methods of representation
" numbers: {: b},{:o},{:d},{:x},{:x}, {:%},{:c} ". Format (all, 15.87623,65,"numbers: {0:b},{0:o},{0:d},{0:x},{0:x}, {0:%} , {1:c}". Format (15,65"numbers: {num:b},{num:o},{num:d},{num:x},{num:x}, {num: %},{CC:C}". Format (num=15,cc=65)Print(A1)print (A2) Print (A3)
Execution Result:
Numbers:1111,17,15,f,f, 1587.623000%,a
Numbers:1111,17,15,f,f, 1500.000000%,a
Numbers:1111,17,15,f,f, 1500.000000%,a
, "optional" adds a delimiter to the number, such as: 1,000,000
. Precision "optional" decimal digits reserved Precision
' ---{:, d}---- '. Format (10000000'---{:. 2f}----'. Format (1.2345) Print(n)print(N1)
Execution Result:
---10,000,000-------1.23----
Format Common formatting
TP1 ="I am {}, age {}, {}". Format ("Seven", 18,'Alex') TP2="I am {}, age {}, {}". Format (*["Seven", 18,'Alex']) TP3="I am {0}, age {1}, really {0}". Format ("Seven", 18) TP4="I am {0}, age {1}, really {0}". Format (*["Seven", 18]) TP5="I am {name}, age {age}, really {name}". Format (name="Seven", age=18) TP6="I am {name}, age {age}, really {name}". Format (**{"name":"Seven"," Age": 18}) TP7="I am {0[0]}, age {0[1]}, really {0[2]}". format ([1, 2, 3], [11, 22, 33]) TP8="I am {: s}, age {:d}, Money {: F}". Format ("Seven", 18, 88888.1) TP9="I am {: s}, age {:d}". Format (*["Seven", 18]) Tp10="I am {name:s}, age {age:d}". Format (name="Seven", age=18) Tp11="I am {name:s}, age {age:d}". Format (**{"name":"Seven"," Age": 18})Print(TP1)Print(TP2)Print(TP3)Print(TP4)Print(TP5)Print(TP6)Print(TP7)Print(TP8)Print(TP9)Print(TP10)Print(TP11)
Execution Result:
Iam seven,age of1, age 2, really 318, Money 88888.10000018
Python string formatting
