Regular Expressions for Translators: Anchors

Have you ever needed to find some text that appears at the beginning or at the end of a segment? How about some text that appears in the middle of a word? Regular expression anchors allow you to do just that.

Download Nora’s Regular Expressions for Translators Cheat Sheet

Here are a few examples where anchors are used to filter segments with SDL Trados Studio's display filter.

First, have a look at the unfiltered text.

In the first example below, I have used a simple regular expression to filter on target segments that have the string "tornillo" at the beginning. Notice that the word "tornillos" is also included, as there is no indication of a word boundary in the regex.

Now, I've filtered to display target segments that end in the word "perno".

The start of segment and end of segment anchors can be used together to enclose the entire contents of the segment, as shown below.

Next, I will use the word boundary anchor, which indicates where a word should start or end. In this example, I'm filtering on the word "tornillo" followed by a word boundary, which means that this won't match the word "tornillos".

When the word boundary anchor is used right before the string "tornill", the filter finds all instances of "tornillo" and "tornillos", but not "atornillada" (segment 4), as the string doesn't appear right after the word boundary in that instance.

The last anchor in the list is the non word boundary anchor. When I use it along with the word "tornillo", I find only instances where the word "tornillos" is found, as the regex means that "tornillo" should not be followed by a word boundary.

Using the non word boundary anchor right before the string "tornill" displays the segment that has the word "atornillada" in it, as the regex indicates that there should not be a word boundary right before "tornill".

As a last example, have a look at this regex that finds source segments that end in the string "bolt", which includes a segment that ends in the word "bolt" and another one that ends in the word "thunderbolt".

If I combine word boundary and end of segment anchors, the filter will display only the segment that ends in the word "bolt", as the word boundary anchors have excluded the word "thunderbolt".

I hope that these simple examples will inspire you to use anchors to find specific text in a variety of use cases.