How to use `string.startsWith()` method ignoring the case?

Question

I want to use string.startsWith() method but ignoring the case.

Suppose I have String "Session" and I use startsWith on "sEsSi" then it should return true.

How can I achieve this?

Answer 1

One option is to convert both of them to either lowercase or uppercase:

"Session".toLowerCase().startsWith("sEsSi".toLowerCase());

This is wrong. See: https://stackoverflow.com/a/15518878/14731

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Another option is to use String#regionMatches() method, which takes a boolean argument stating whether to do case-sensitive matching or not. You can use it like this:

String haystack = "Session";
String needle = "sEsSi";
System.out.println(haystack.regionMatches(true, 0, needle, 0, 5));  // true

It checks whether the region of needle from index 0 till length 5 is present in haystack starting from index 0 till length 5 or not. The first argument is true, means it will do case-insensitive matching.

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And if only you are a big fan of Regex, you can do something like this:

System.out.println(haystack.matches("(?i)" + Pattern.quote(needle) + ".*"));

(?i) embedded flag is for ignore case matching.

Answer 2

I know I'm late, but what about using StringUtils.startsWithIgnoreCase() from Apache Commons Lang 3 ?

Example :

StringUtils.startsWithIgnoreCase(string, "start");

Just add the following dependency to your pom.xml file (taking the hypothesis that you use Maven) :

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.11</version>
</dependency>

Answer 3

myString.toLowerCase().startsWith(starting.toLowerCase());

Answer 4

try this,

String session = "Session";
if(session.toLowerCase().startsWith("sEsSi".toLowerCase()))

Answer 5

You can use someString.toUpperCase().startsWith(someOtherString.toUpperCase())

Answer 6

StartsWith(String value, bool ignoreCase, CultureInfo? culture) e.g:

string test = "Session";
bool result = test.StartsWith("sEsSi", true, null);
Console.WriteLine(result);

point: in VS by right-clicking on StartsWith and then "pick definition" can see all overloading method