Testing Whether String Starts with or End with Another String

Testing whether string starts with or end with another string

There are built in methods:

"String".start_with? "S" # true
"String".end_with? "4" # false

How to check if a string starts and ends with specific strings?

This regular expression:

^https://.*/MyTest$

will do what you ask.

^ matches the beginning of the string.

https:// will match exactly that.

.* will match any number of characters (the * part) of any kind (the . part). If you want to make sure there is at least one character in the middle, use .+ instead.

/MyTest matches exactly that.

$ matches the end of the string.

To verify the match, use:

Regex.IsMatch(str, @"^https://.*/MyTest$");

More info at the MSDN Regex page.

How do you check if string ends with another string in Ada?

A slight simplification of Simon's answer:

function Ends_With (Source, Pattern : String) return Boolean is
begin
   return Pattern'Length <= Source'Length 
     and then Source (Source'Last - Pattern'Length + 1 .. Source'Last) = Pattern;
end Ends_With;

How to check for [ ] at beginning and end of string

There is no need for a regex, use start_with and end_with:

s = "[text\nhere]"
puts s.start_with?("[") and s.end_with?("]")
# => true

See Ruby demo

If you need a regex, you may use

/\A\[.*\]\z/m

to check if any string starts with [ and ends with ].

Explanation:

• \A - start of a string
• \[ - a literal [
• .* - 0+ any characters, even incl. a newline due to the /m modifier)
• \] - a closing ]
• \z - the very end of the string.

See the regex demo

find whether the string starts and ends with the same word

You can use backreference within regex

^(\w+\b)(.*\b\1$|$)

This would match a string only if it

• starts and ends with the same word
• has a single word

Check if string starts or ends with vbCrLf

Try this

StartsWith - checks the first part of a String.

    Dim s As String = "vbCrLf bla bla bla"

    If s.StartsWith("vbCrLf") Then
        MsgBox("Yes")
    End If

EndsWith - checks the last characters of a String.

    Dim s As String = "bla bla bla vbCrLf"

    If s.EndsWith("vbCrLf") Then
        MsgBox("Yes")
    End If

Regexp - How to check whether a string starts OR ends with given character?

If you just have one character at the beginning or the end, it's as simple as saying this:

/^!|!$/

No need for a capture group.

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Update: To make sure you get either an exclamation mark and ten letters or ten letters and an exclamation mark, build your pattern like this:

/^!?[a-z0-9]{1,10}$|^[a-z0-9]{1,10}!?$/

It looks like it's repeating itself, but it's actually way cheaper and faster than having three capture groups.

I put together a unit test in regex101 for this.

How to check if a string starts with another string in C?

Apparently there's no standard C function for this. So:

bool startsWith(const char *pre, const char *str)
{
    size_t lenpre = strlen(pre),
           lenstr = strlen(str);
    return lenstr < lenpre ? false : memcmp(pre, str, lenpre) == 0;
}

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Note that the above is nice and clear, but if you're doing it in a tight loop or working with very large strings, it does not offer the best performance, as it scans the full length of both strings up front (strlen). Solutions like wj32's or Christoph's may offer better performance (although this comment about vectorization is beyond my ken of C). Also note Fred Foo's solution which avoids strlen on str (he's right, it's unnecessary if you use strncmp instead of memcmp). Only matters for (very) large strings or repeated use in tight loops, but when it matters, it matters.

Checking whether a string starts with XXXX

aString = "hello world"
aString.startswith("hello")

More info about startswith.

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