Summary of formatting output usage in python

This example summarizes the format output usage in python. For your reference, see the following example: This article summarizes the format output usage in python. We will share this with you for your reference. The details are as follows:

Python has two types of formatting output syntax.

One method is similar to the C language printf, called Formatting Expression

>>> '%s %d-%d' % ('hello', 7, 1)  'hello 7-1'

Another Method is similar to C #, called String Formatting Method CILS.

>>> '{0} {1}:{2}'.format('hello', '1', '7')  'hello 1:7'

The first method can specify the floating point precision, for example

>>> '%.3f' % 1.234567869  '1.235'

Specify the floating point precision dynamically during runtime

But how can I dynamically specify the floating point precision through parameters when the code is running?

The magic of python is that it provides a very convenient syntax. You only need to add a * before typecode (here is f), and the precision of the floating point is specified by the number before it.

>>> for i in range(5):  ... '%.*f' % (i, 1.234234234234234)  ...  '1'  '1.2'  '1.23'  '1.234'  '1.2342'

The output results show that the precision is dynamically specified during running, saving the concatenation of formatted strings.

You can use String Formatting Method CILS to complete functions more concisely.

>>> for i in range(5):  ...  '{0:.{1}f}'.format(1 / 3.0, i)  ...  '0'  '0.3'  '0.33'  '0.333'  '0.3333'

Implement a simple template tool

The template language provided by Django allows us to bind python variables to the html file through a dict (dictionary). In fact, we can simply replace the text with the format output of python.

>>> replay = """ ... Hello World Cup... ... Germany vs Brazil ... %(germany)d : %(brazil)d"""  >>> print(replay % {'germany': 7, 'brazil': 1})  Hello World Cup...  Germany vs Brazil  7 : 1

You can also play it like this

>>> germany = 7  >>> brazil = 1  >>> '%(germany)d : %(brazil)d' % vars()  '7 : 1'

Access Object attributes and dictionary key values in formatted strings

>>> 'My {1[kind]} runs {0.platform}'.format(sys, {'kind': 'pc'})  'My pc runs linux'  >>> 'My {map[kind]} runs {sys.platform}'.format(sys=sys, map={'kind': 'pc'})  'My pc runs linux'

Access list elements through subscript (positive integer) in formatted strings

>>> somelist = list('SPAM')  >>> 'first={0[0]}, third={0[2]}'.format(somelist)  'first=S, third=A'  >>> 'first={0}, last={1}'.format(somelist[1], somelist[-1])  'first=P, last=M'  >>> parts = somelist[0], somelist[-1], somelist[1:-1]  >>> 'first={0}, last={1}, middle={2}'.format(*parts)  "first=S, last=M, middle=['P', 'A']"  >>>

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