1 `<:val:>`

<:val expr [fmt="plain"]:>

Causes the Python expression expr to be evaluated, and the resulting Python object is converted to a string and displayed at that place in your document. (All Python objects can be turned into strings.)

For example, if you would like to display the result of 5 + 2:

<:val `5 + 2`:>

The <:val:> tag is just like calling the str() function in Python on the resulting object, with one exception: if the object is the None object, <:val:> prints an empty string "" instead of the string "None". The following two tags show the value of the variable named myVar and show nothing, respectively:

<:val `myVar`:>
<:val `None`:>

<:val:> only accepts Python expressions as its attribute, not full Python statements. That means that you cannot assign objects to variable names with this tag. Use the <:set:> (see section 2.2, page ) tag to assign objects to variable names. You can, however, call functions and classes, and make boolean expressions with and, or, and not. For example, if you want to call a function myFunction, which returns some HTML to include in your document:

<:val `myFunction()`:>

The string printed by <:val:> is just a plain string by default; no special formatting takes place. Sometimes you want the string to be formatted in a special way: you want HTML special characters escaped, or you want all characters escaped so that the string can be made part of a URL. The fmt argument lets you specify one of many common formatting or escaping operations on the string:

"plain" or "plaintext": No escaping. This is the default.
"latin" or "latinquote": Escape only extended characters to ISO Latin1 entities: í become í, etc.
"html" or "htmlquote": Escape only things that would break HTML formatting: < > & `` '. These characters are escaped to the named HTML entities for them: <, etc.
"uri", "url", "uriquote" or "urlquote": Escape all URL-unsafe characters to %XX format.
"fulluri" or "fullurl": Escape every character into URL-safe %XX format.
"base64": base64 encodes the string.

Examples of fmt, with the output shown after each example:

<:set myVar "Click here >>>>":>

<:val `myVar`:>
Click here >>>>

<:val `myVar` fmt="html":>
Click here &gt;&gt;&gt;&gt;

<:val `myVar` fmt="url":>
Click%20here%20%3E%3E%3E%3E

<:val `myVar` fmt="fullurl":>
%43%6C%69%63%6B%20%68%65%72%65%20%3E%3E%3E%3E

The <:val:> tag is equivalent to the following code executed in a Python component:

import DT.DTCommon
print DT.DTCommon.ValFmtRgy[fmt](expr)

1 <:val:>

1 `<:val:>`