Here is how to check if the string "abcde" is exactly 5 characters:
{{str ≠ len | abcde | 5
| Not equal.
| Equal.
}}
Which returns this:
Equal.
Templates have a problem to handle parameter data that contains equal signs "=". But that is easily solved by using numbered parameters. Here we check if the string "ab=cde" is exactly 100 characters:
It probably is a good habit to always use the numbered parameters, since you might not know beforehand exactly how the data will look that your template will feed to this meta-template.
This template would be equivalent to templates named {{str != len}} or {{str == len}}, but we can't use those template names since they don't work well in MediaWiki.
Even though this is a string handling template it uses efficient code. (While some of the other string handling templates are probably so heavy on the servers that we perhaps should not use them.)
Templates have problems to handle parameter data that contains pipes "|", unless the pipe is inside another template {{name|param1}} or inside a piped link [[Help:Template|help]]. Thus templates can not handle wikitables as input unless you escape them by using the {{!}} template. This makes it hard to use wikitables as parameters to templates. Instead the usual solution is to use "HTML wikimarkup" for the table code, which is more robust.
