# Isalnum deprecated?

**URL:** <https://discourse.julialang.org/t/isalnum-deprecated/8504>\
**Category:** Internals & Design\
**Created:** [January 21, 2018, 11:21am UTC](https://discourse.julialang.org/t/isalnum-deprecated/8504 "2018-01-21T11:21:15Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ScottPJones](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/scottpjones/32/146_2.png) [@ScottPJones](https://discourse.julialang.org/u/ScottPJones)\
**Post date:** [January 21, 2018, 11:21am UTC](https://discourse.julialang.org/t/isalnum-deprecated/8504/1 "2018-01-21T11:21:15Z")

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I just ran into a bunch of new deprecations on master, it seems that `isalnum` has been deprecated, and it is suggested to use `isalpha(c) || isnumeric(c)` instead.  
`isalnum` is very heavily used in some code, for example where identifiers are defined as starting with `isalpha` and then allowing any number of `isalnum` characters, and the change can have a large impact on performance (since `isalnum` would generally be implemented not by two lookups, but by a single lookup into a two-stage bit table indexed by code point, exactly the same as the other `is*` POSIX functions).