Print/format string formatting instances in Python

the Python string is formatted using the "character% format 1% format 2 characters"% (variable 1, variable 2), and the% format represents the type of the accepted variable. Simple examples of use are as follows

# Example: String formatting
Name = ' 17jo '
print ' www.%s.com '%name
>> www.111cn.net

Name = ' 17jo '
Zone = ' com '
print ' www.%s.%s '% (name,zone)
>> www.111cn.net

The string is formatted with a different format symbol after the percent sign, representing the different types to be converted, and the specific representation symbol is shown below.

Format symbol representation type
%s string
%d/%i decimal Integer
%u decimal integer
%o Eight-binary integers
%x/%x hexadecimal integer
%e/%e Scientific counting
%f/%f floating Point
% OUTPUT%

When the format symbol is a number, it can be preceded by an amount and a fill-in position such as:%[0][total number of digits [.] [Decimal place] to set the style to be converted, using the following method:

# example: Numeric formatting
nyear = 2018
Nmonth = 8
Nday = 18
# formatted date%02d number to two-bit integer vacancy fill 0
print '%04d-%02d-%02d '% (nyear,nmonth,nday)
>> 2018-08-18 # Output results

Fvalue = 8.123
print '%06.2f '%fvalue # reserved 2-bit decimal floating-point with a width of 6
>> 008.12 # Output

print '%d '%10 # output decimal
>> 10
print '%o '%10 # output octal
>> 12
print '%02x '%10 # output two-bit hex, letter lowercase blank complement 0
>> 0a
print '%04x '%10 # output four-bit hex, letter capital Vacancy 0
>> 000A
print '%.2e '%1.2888 # Output floating-point type with scientific notation reserved 2 decimal places
>> 1.29e+00

In this way, we have shown how to replace the specified field. We can also make precise formatting by adding a colon after the format indicator. For example:

Python:format

# Field 0:left justify, pad to characters
# Field 1:right Justify, pad to 6 characters
FMT = ' {0:15} ${1:>6} '

Fmt.format (' registration ', +)
' Registration $35 '

Fmt.format (' Tutorial ', +)
' Tutorial $50 '

Fmt.format (' Banquet ', ()
' Banquet $125 '

Formatting indicators can be referenced by nesting.

FMT = ' {0:{1}} '

width = 15
Fmt.format (' Invoice #1234 ', width)
' Invoice #1234 '

width = 35
Fmt.format (' Invoice #1234 ', width)
' Invoice #1234 '

You can specify the alignment of the string that you want to length.
Effect characters:
< (default) align Left
> Right Alignment
^ Middle Alignment
= (for numbers only) after the decimal point

Formatting indicators can contain a presentation type to control formatting. For example, a floating-point number can be formatted as a general format or represented by a power.

>>> ' {0:g} '. Format (3.75)
' 3.75 '
>>> ' {0:e} '. Format (3.75)
' 3.750000e+00 '

There are many types of impressions. The complete list is in the 2.6 document. Some examples are listed here.

' B '-binary. The number is output as a base of 2.
' C '-character. Converts an integer to the corresponding Unicode string before printing.
' d '-decimal integer. The number is output as a base of 10.
' O '-eight binary. The number is output as a base of 8.
' x '-16 binary. The number is output in 16, and the number of digits above 9 is in lowercase letters.
The ' e '-power symbol. Print numbers in scientific notation. Use ' e ' to indicate power.
' G '-general format. The value is output in fixed-point format. When the number is particularly large, it is printed in a power form.
' N '-number. When the value is an integer and ' d ', the values are the same as the ' G ' when they are floating-point numbers. The difference is that it inserts a numeric delimiter according to the locale.
'% '-percent. Multiply the value by 100 and then print in fixed-point (' F ') format, followed by a percent semicolon.

Classes and types can define a __format__ () method to control how they are formatted. It will accept a format indicator as an argument:

def __format__ (self, Format_spec):
If Isinstance (Format_spec, Unicode):
return Unicode (self)
Else
Return str (self)

There is also a built-in format () method that can be used to format a value. It invokes the __format__ () method of the type and passes the format indicator as a parameter.

>>> format (75.6564, '. 2f ')
' 75.66 '

Print/format string formatting instances in Python