string

How to print an array in Android Log output (Logcat)

If you need to dump the contents of an array to the Android Log (Logcat) output, I can confirm that this approach works, at least with simple arrays of integers and strings that know how to print themselves:

Log.i("MyAndroidClass", Arrays.toString(arr));

If you’re trying to print more complicated arrays of custom objects you’ll probably need to implement good toString methods on those objects, and then this technique should work.

Scala code to read a text file to an Array (or Seq)

As a quick note, I use code like this read a text file into an Array, List, or Seq using Scala:

def readFile(filename: String): Seq[String] = {
    val bufferedSource = io.Source.fromFile(filename)
    val lines = (for (line <- bufferedSource.getLines()) yield line).toList
    bufferedSource.close
    lines
}
Creating random strings and shuffling them (for JavaFX ListView) alvin January 17, 2017 - 4:35pm

As a short “note to self,” I just used this Scala code to (a) create a list that contains random strings of different lengths, then (b) shuffle the list of strings to create a more random effect:

How to use multiple regex patterns with replaceAll (Java String class)

Java FAQ: How can I use multiple regular expression patterns with the replaceAll method in the Java String class?

Here’s a little example that shows how to replace many regular expression patterns with one replacement string in Scala and Java. I’ll show all of this code in Scala’s interactive interpreter environment, but in this case Scala is very similar to Java, so the initial solution can easily be converted to Java.

A Java method to replace all instances of a pattern in a String with a replacement pattern

Note: The code shown below is a bit old. If you want to perform a “search and replace” operation on all instances of a given pattern, all you have to do these days is use the replaceAll method on a Java String, like this:

String s = "123 Main Street";
String result = s.replaceAll("[0-9]", "-");

That second line of code returns the string “--- Main Street”. I kept the information below here for background information.

PHP: How to remove non-printable characters from strings

PHP FAQ: How do I remove all non-printable characters from a string in PHP?

I don’t know of any built-in PHP functions to remove all non-printable characters from a string, so the solution is to use the preg_replace function with an appropriate regular expression.