counter

Kotlin: A for loop that counts up to some maximum integer value alvin December 1, 2018 - 3:05pm

As a brief note to self, I was just converting some Java code to Kotlin, and the correct way to convert this Java for loop that uses i as a counter:

for (int i=0; i<tabLayout.tabCount; i++) { ...

is with this Kotlin for loop:

for (i in 0 until tabLayout.tabCount) { ...

The key there for me is the 0 until part of the syntax.

A Linux shell script to rename files with a counter and copy them

As a brief note today, I was recently looking for all Messages/iMessage files that are stored on my Mac, and I used this shell script to copy all of those files — many of which have the same name — into a directory named tmpdir, giving them all new names during the copy process:

count=1
for i in `cat myfiles`
do
    fname=`basename $i`
    cp $i tmpdir/${count}-${fname}
    count=`expr $count + 1`
done

How to use Scala ‘for’ loops (expressions) with multiple counters (multi-dimensional arrays)

This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 3.2, “How to use Scala for loops with multiple counters.”

Problem

You want to create a loop with multiple counters, such as when iterating over a multi‐dimensional array.

Solution

You can create a for loop with two counters like this:

How to read and write from a file in a Linux bash shell script

I’m currently writing a complicated Linux bash shell script where I need to keep a counter in an external file, and to do so, I need to be able to write to a file and then read from that file.

In short, this is how I write my counter to that file:

# create a variable to represent the filename
COUNTER_FILE="counter.tmp"

# write to the file
echo "0" > $COUNTER_FILE

Later in the code I increment the counter and write it to the file like this:

Linux shell scripts: How to increment a counter in a shell script

Unix/Linux shell script FAQ: Can you share a simple Linux shell script that shows how to count, i.e., a shell script that increments a counter in a for loop or while loop?

Sure, I just needed to increment a while loop counter myself, so I thought I'd share my example shell script code here.