What is Python string template

Python is an interpreted, object-oriented high-level programming language. It is easy to learn because its syntax emphasizes readability, which reduces program maintenance costs. Many programmers prefer using Python because there is no compilation step and testing and debugging are done quickly.

Python Web Templates

Templating, especially web page templating, represents data in a form that is usually intended to be readable by the viewer. In its simplest form, a template engine replaces values ​​with a template to produce output.

In addition to string constants and deprecated string functions (moved to string methods), Python's string module also includes string templates. The template itself is a class that receives a string as a parameter. Objects instantiated from this class are called template string objects. Template strings were first introduced in Python 2.4. Where the string formatting operator uses the percent sign for substitution, the template object uses the dollar sign.

$$ is an escape sequence; it is replaced by a $.

$ Names a replacement placeholder that matches the mapping keyword of . By default, must be spelled out for Python identifiers. The first non-identifier character after the $ character terminates this placeholder specification.

$ {} is equivalent to $ . It is required when a valid identifier character follows a placeholder but is not part of the placeholder, such as $ {noun} ification.

Outside of these uses of the dollar sign, any appearance of $ will cause a ValueError to be raised. The methods available through template strings are as follows:

class string.

Template (template): The constructor takes a single parameter, the template string.

Replacement (mapping, ** keywords): Method used to replace the string value (mapping) of the template string value. Maps are dictionary-like objects whose values ​​can be accessed as dictionaries. If the keywords parameter is used, it represents placeholders. In the case of using mappings and keywords, the latter takes precedence. If the placeholder is missing from the map or keyword, KeyError is thrown.

Safe_substitute(mapping, ** keywords): A function similar to substitute(). However, if a placeholder is missing from the mapping or keyword, the original placeholder is used by default, thus avoiding KeyError. Additionally, any occurrence of "$" returns a dollar sign.

Template objects also have a publicly available property:

Template is the object passed to the constructor template parameter. Although read-only access is not enforced, it is best not to change this property within a program.

The following example shell session is used to illustrate the template string object.

>>> from string import Template

>>> s = Template('$when, $who $action $what.')

>>> s.substitute(when='In the summer', who='John', action='drinks', what='iced tea') 'In the summer, John drinks iced tea.'

>>> s.substitute(when='At night', who='Jean', action='eats', what='popcorn') 'At night, Jean eats popcorn.'

>>> s.template '$when, $who $action $what.'

>>> d = dict(when='in the summer')

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