#java substring

[codelivly]

Java Substring

A substring is a part of String. Substring, in other words, is a subset of another String. The built-in substring() method of the Java String class extracts a substring from a given string using the index values passed as an argument. StartIndex is inclusive and endIndex is exclusive when using the substring() function. If the string is “computer,” the substrings are com, compu, ter, and so…

View On WordPress

[ilearntsomethingnew-blog]

nesting of substrings is faster than split!

Had my "whaaat?" moment of the day when I wrote some experimental Java code and did some performance analysis against the conventional method. Working on a code where I need to split a String in first and last name and had to trim those to 15 characters. Without further stories, will post the code directly. int lastSpaceCharacterLocation = customerName.lastIndexOf(" "); String firstName = StringUtils.substring(StringUtils.substring(customerName, 0, lastSpaceCharacterLocation), 0, 15); String lasttName = StringUtils.substring(StringUtils.substring(customerName, lastSpaceCharacterLocation + 1), 0, 15); I chose this over the conventional method of String[] aa = customerName.split(" "); StringUtils.substring(aa[0], 0, 15); StringUtils.substring(aa[aa.length - 1], 0, 15); To my surprise the first method was around 6 times faster than conventional one! How did I compare performance? I know I am not a per specialist, but here's how I did it: package com.test; import org.apache.commons.lang.StringUtils; /** * Created by IntelliJ IDEA. User: sumit.goyal Date: 2/2/12 Time: 3:25 PM To change this template * use File | Settings | File Templates. */ public class StringPerfTest { public static void main(String[] args) { String customerName = "SumitSumitSumitasdfadsf SumitSumitSumitsadssss"; final long start1 = System.currentTimeMillis(); System.out.println(start1); for (long i = 0; i < 10000000; i++) { int lastSpaceCharacterLocation = customerName.lastIndexOf(" "); StringUtils .substring(StringUtils.substring(customerName, 0, lastSpaceCharacterLocation), 0, 15); StringUtils .substring(StringUtils.substring(customerName, lastSpaceCharacterLocation + 1), 0, 15); } final long stop1 = System.currentTimeMillis(); System.out.println(stop1); final long start2 = System.currentTimeMillis(); System.out.println(start2); for (long i = 0; i < 10000000; i++) { String[] aa = customerName.split(" "); StringUtils.substring(aa[0], 0, 15); StringUtils.substring(aa[aa.length - 1], 0, 15); } final long stop2 = System.currentTimeMillis(); System.out.println(stop2); System.out.println(stop1 - start1); System.out.println(stop2 - start2); } }