Extract string using StringUtils

Question

Let's take a string "aabaabaa" and I want to know the position of "aa" in middle or from last.

For example position of "aa" from right should be : 6 (taking start insex as 0)

Answer 1

This can easily be done using StringUtils present in Apache commons. Here is the complete example on the usage.

public static int indexOfIgnoreCase(String str,
                                    String searchStr,
                                    int startPos)

Case in-sensitive find of the first index within a String from the specified position.

A null String will return -1. A negative start position is treated as zero. An empty ("") search String always matches. A start position greater than the string length only matches an empty search String.

StringUtils.indexOfIgnoreCase(null, *, *)          = -1
StringUtils.indexOfIgnoreCase(*, null, *)          = -1
StringUtils.indexOfIgnoreCase("", "", 0)           = 0
StringUtils.indexOfIgnoreCase("aabaabaa", "A", 0)  = 0
StringUtils.indexOfIgnoreCase("aabaabaa", "B", 0)  = 2
StringUtils.indexOfIgnoreCase("aabaabaa", "AB", 0) = 1
StringUtils.indexOfIgnoreCase("aabaabaa", "B", 3)  = 5
StringUtils.indexOfIgnoreCase("aabaabaa", "B", 9)  = -1
StringUtils.indexOfIgnoreCase("aabaabaa", "B", -1) = 2
StringUtils.indexOfIgnoreCase("aabaabaa", "", 2)   = 2
StringUtils.indexOfIgnoreCase("abc", "", 9)        = 3

Parameters:

• str - the String to check, may be null
• searchStr - the String to find, may be null
• startPos - the start position, negative treated as zero

Returns: The first index of the search String, -1 if no match or null string input