Is regex faster than replace?

Two-regex is 10 times slower than string replacement, and regex/lambda 25 times slower. Two-regex is now 15.9 times slower than string replacement, and regex/lambda 38.8 times slower. It seems as the input gets longer the regular expressions get slower and slower in comparison.

Are regex fast?

Regular expressions are one possible type of parser, and for the standard case they do parse the string letter by letter (they never require contextual information), so the question is a little unclear. But at least in theory, true regular expressions are very fast indeed.

Which is faster regex or string contains?

To determine which is the fastest you will have to benchmark your own system. However, regular expressions are complex and chances are that String. Contains() will be the fastest and in your case also the simplest solution.

How fast is regex matching?

The bad regular expression took on average 10,100 milliseconds to process all 1,000,000 lines, while the good regular expression took just 240 milliseconds.

Which is faster, regex or string operations?

At best, the regular expression operation can do what’s optimal to do the string manipulations. Regular expressions are not used because they can do anything faster than plain string operations, it’s used because it can do very complicated operations with little code, with reasonably small overhead.

Is there a function that does not use regex?

Like with the replace command, there is a String.Split () function that does not use regex. It will be faster when splitting on a character (or substring) and give you the same results. By default, the switch statement does exact matches. But it does have an -regex option to use regex matches instead.

Which is faster, regexp _ replace or impala replace?

Because this function does not use any regular expression patterns, it is typically faster than regexp_replace () for simple string substitutions. There are some alternative methods that you can use if you are using a lower version of Cloudera impala.

How to speed up regex replacement in Python?

One thing you can try is to compile one single pattern like “\\b (word1|word2|word3)\\b”. Because re relies on C code to do the actual matching, the savings can be dramatic. As @pvg pointed out in the comments, it also benefits from single pass matching. If your words are not regex, Eric’s answer is faster.