Python F-Strings Number Format Cheat Sheet

 Inside quotes, an f-string consists of two parts: (1) A regular string literal, i.e. text and (2) The replacement field

contains the Python expression for evaluation format and format control.

 Double quotes are used here, but single quotes or Triple quotation marks.

 F-string may contain only one replacement field: f”{replacement_field}”

Replace Field

{f-expression=!conversion:format_specifier}

 A replacement field is represented by a pair of curly braces: { }

 The replacement field consists of a Python expression for evaluation, with optional Debug mode (=), type conversion (!), and format specification (:).

 Substitute into f-string template:

f" text{f expression=!conversion:format_specifier} text..."

0 : Symbol awareness, zero padding for numbers 
 width : Minimum total field width
 September : Number separator (',' or '_')  .precision : How many digits are displayed for floating point numbers;  String maximum field width type : According to data Representation type used by type
 Notes :  notation , #, 0, September,Accuracy and  type  versus  digital format  is of particular interest, focus on this cheat sheet. For general handling of F-Strings, see my cheat sheet Python F-Strings Basics
.

: n

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Integer : d, b, o, x, X, C = symbol float: e, E, f, F , g, G, % Signature and Delimiter Options + Signs are used for both positive and negative numbers - notation is only used for negative numbers ( default) space leading spaces for positive numbers and minus signs for negative numbers separated Device , comma. Decimal Integers and Floating Points: Thousand Separator _ underscore. Decimal Integers and Floating Points: Thousands Separator; b, o, x, and X Types: Every Four Digits Separator Example: Symbols and Delimiters #(+): add a sign to both positive and negative number # sign (-): sign is used only for negative numbers #Unsigned equals sign (-) f"{3:+} or {-3:+}" '+3 or -3 ' f"{3:-} or {-3: -}" '3 or -3' #Symbol (space): The leading space of a positive number and Negative sign for negative numbers # Symbol (+ ), delimiter(,) f"{3} or {-3}" '3 or -3' f"{3: } or {-3: }" '3 or -3' f"{10000 :+,}" '+10, 000' # padding(?), alignment( f"{10000:? '+10,000????' Sign Aware Padding Use =Alignment Option to force padding determined by the symbol to be placed ( Padding and width specifications after the number if any) but before the number. This is useful for number representations like "+000042". This alignment option is only available for number types. 0-option produces sign-aware zero-padding, Like the=alignment option padded with '0'. It is produced by prepending a '0' to the field width specification. #fill(?), alignment(=), sign(+), width(5) # full (0), alignment (=), sign (+), width (5) f"{3:?=+5}" ' +???3' f"{3:0=+5}" '+0003' # sign(+), 0-option, width(5) # 0-options,width( 5) f"{3:+05}" '+0003' f"{3:05}" '00003 ' Decimal integer type # print symbols 33-41 with unicode decimal representation Integer representation type d Decimal Integer: Number in base 10 other not any as d n number. Same as d, except that the current locale is used to set the appropriate number separator f "binary: {i:#b }; octal: {i:#o}; hex: {i:#x} or {i:#X}" b # #-option Add prefix Binary: A number in base 2. o Octal: A number in base 8. i=13 # Represents decimal 13 in binary, octal and hexadecimal f"binary: {i:b}; octal: {i:o}; hex: {i:x} or {i:X}" x, X Hexadecimal: a base 16 number. x and X for lowercase and uppercase for numbers> 9 C Unicode characters. Convert decimal integer to corresponding unicode character #-option: use# - option to add prefix #b: Add prefix 0b #o : Add prefix 0o #x: add prefix 0x #X: add prefix 0X Example: Integer Type 'Binary: 1101; Octal: 15; Hexadecimal: d or D' f"{i:0=#8b}" '0b001101' # returns the decimal representation unicode character 36 # fill (0), align (=), #-option, width (8), type (b) ' Binary: 0b1101; Octal: 0o15; Hex: 0xd or 0XD' # Binary zero padding # Binary file with prefix and zero padding f"{i:08b}" '00001101' f"{i:#08b}" '0b001101' f"{36:c}" '$' print(''.join([f"{x:c}" for x in range(33,42)])) !"#$%&'() # type d is the default value for integers, so no need # delimiter (,) and class Type(d) f"{10000:,d}" '10,000' f"{10000:,}" #Use the locale specific number format, set the locale Import Locale locale.setlocale(locale.LC_ALL, '') # Then use format type 'n' '10,000' #Separator(_),Type(b) F"{ 1200:_b}" '100_1011_0000 ' f"{106:n}" '1,000,000' Floating point representation type type Name For a given precisionp... e, E Scientific notation coefficients have 1 decimal point and p digits after the decimal point. # lowercase g and uppercase G f, F Fixed-point notation Yesp digits after the decimal point. G, G General format round ds numbers are converted to p significant digits, and then according to the size in fixed point or Formatted in scientific notation. % percentage Multiply the number by 100 and display it in fixed f format followed by a percent sign.  The default value for floating point numbers is p=6. Default value in decimal. The decimal p is large enough to display all coefficient digits.  Lowercase and uppercase: Make sure scientific notation is to display "e ' or 'E' ' and whether to use 'nan' versus 'NAN' and 'inf' versus 'INF'. Example: Simple floating point comparison # %-style with precision=1 # lowercase e and uppercase E #lowercase f and uppercase F f"{1/2:.1 %}" '50.0 %' f"{1000:.1e} with {1000:.1E}" '1.0e+03 and 1.0E+03' f"{1000:.1f} and {1000:.1F}" '1000.0 vs 1000.0' # Lowercase and uppercase NaN means F "{1000:.1g} and {1000:.1G}" '1e+03 and 1E+03' nan=float('nan') f"{nan: f} vs {nan:F}" 'nan vs NAN'