# Trimming unprintable characters

**URL:** <https://forum.kirupa.com/t/trimming-unprintable-characters/320403>\
**Category:** flash\
**Created:** [March 22, 2011, 5:48pm UTC](https://forum.kirupa.com/t/trimming-unprintable-characters/320403 "2011-03-22T17:48:54Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jasonfahy](https://avatars.discourse-cdn.com/v4/letter/j/73ab20/32.png) [@jasonfahy](https://forum.kirupa.com/u/jasonfahy)\
**Post date:** [March 22, 2011, 5:48pm UTC](https://forum.kirupa.com/t/trimming-unprintable-characters/320403/1 "2011-03-22T17:48:54Z")

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Hello,

I’m fumbling my way along, writing a schedule-building utility for my online students. I want it to load class information from a .txt file, written in NotePad.

I’ve loaded the data as a string, then I used .split("  
") to slot the lines of the file into an array. So far so good.

Now, I want the program to forgive empty lines at the end of the file, so I mashed Enter several times as a test and traced the array - I get this:

> 

Item number 0 is apple  
Item number 1 is banana  
Item number 2 is cheese  
Item number 3 is dog food  
Item number 4 is eggs  
Item number 5 is  
Item number 6 is  
Item number 7 is  
Item number 8 is  
Item number 9 is  
Item number 10 is undefined

Desired behavior is to hack off elements 5 through 10, the ones that don’t contain human-readable characters. (I assume 5 through 9 are carriage return+linefeed, and 10 is some end-of-file thing? What does Ctrl-Z look like?)

My cunning plan was going to be (pseudocode)

while (the last element isn’t alphanumeric)  
{  
.pop() the array  
}

To my surprise, I’m having major problems finding an “is alphanumeric” or “is printable” method; the closest I’ve found is isNaN which won’t cut it.

Can someone point me in the right direction?

Cheers,  
JF

PS: If the solution requires regular expressions, please type slowly. I know almost nothing about those so far.