title, linktitle, description, godocref, date, publishdate, lastmod, categories, menu, keywords, signature, workson, hugoversion, relatedfuncs, deprecated, aliases
| title | linktitle | description | godocref | date | publishdate | lastmod | categories | menu | keywords | signature | workson | hugoversion | relatedfuncs | deprecated | aliases | 
| in |  | Checks if an element is in an array or slice--or a substring in a string---and returns a boolean. |  | 2017-02-01 | 2017-02-01 | 2017-02-01 |  |  |  |  |  |  |  | false |  | 
The elements supported are strings, integers and floats, although only float64 will match as expected.
In addition, in can also check if a substring exists in a string.