String Comparison Not Working Properly

Why is this string comparison not working? C

Besides the issues mentioned in the comments: you can't compare strings like that:

if(uAts == rline) 

That wil compare the addresses of the char arrays and these will always be different. Use

if( strcmp( uAts, rline ) == 0 )

instead. strcmp() will compare the contents of two NUL terminated char arrays (aka "strings" in C).

C# String comparison not working when compared with a value received over network

The problem was in the presence of an empty character in the end which failed the comparison.

When the Code.Length was checked it was 6 while the length of Admin was 5.

Thus the error was removed by taking a substring of the responseData without the last empty character.

public string ClientReceive()
    {
        try
        {
            stream = client.GetStream();
            byte[] data;
            data = new Byte[256];
            String responseData = String.Empty;
            Int32 bytes = stream.Read(data, 0, data.Length);
            responseData = Encoding.ASCII.GetString(data, 0, bytes);
            responseData = responseData.Substring(0, responseData.Length-1); // This will remove the last character
            return responseData;
        }
        catch (Exception ex)
        {
            DisplayAlert("Error", ex.Message, "OK");
            return null;
        }
    }

Special Thanks to @bommelding and @Damien_The_Unbelievable for directing me to the correct path.

Java string comparison not working?

You have used the first comparison correctly, but later on, you got it the wrong way some how.

Always use equals() method when comparing the content of strings, as you did in the first case.

Also, if its not working somehow, it may be because you have leading or trailing whitespace in your string. Try using it this way: -

if (grades[i].trim().equals("IG"))

Why comparing Strings in MySQL query is not working

First of all, I must acknowledge the points made by @Uueerdo were actually the the main cause of this issue. Even I was somewhat sure that there are some hidden characters in the string causing all the issue but I was not sure how to find and fix that offending character.

Also, the approach suggested by @Uueerdo to check and replace the offending character using the ASCII code seems quite legit but as he himself mentioned that this process will take lot's of time and one have to manually check every string for that one offending character and then replace it.

Luckily after spending couple of hours on it, I came up with a much faster approach to fix the issue. For that, first of all I would like to share my use case.

My first query was for selecting all the strings from a database and printing the result on page.

$result = mysqli_query($conn, "SELECT * from table_name");
while($row = mysqli_fetch_array($result)){
   $string_var = $row["string_name"]; 
   echo $string_var;
   echo "<br>";
}

The above code was working as expected and printing all the string_name from the table. Now, if I wanted to use the variable $string_var for another SELECT query in the same table, it was giving me 0 results.

$result = mysqli_query($conn, "SELECT * FROM table_name");
while($row = mysqli_fetch_array($result)){
    $string_var = $row["string_name"];
    echo "String Name : ".$string_var."";
    $sec_result = ($conn, "SELECT * FROM table_name WHERE string_var='$string_name'");
    if(mysqli_num_rows($sec_result) > 0){
        echo "Has Results";
    } else {
        echo "No Results";
    }
}

In this snippet, my second query $sec_result was always giving me No Results as output.

What I simply did to fix this issue.

$result = mysqli_query($conn, "SELECT * FROM table_name";
while ($row = mysqli_fetch_array($result)){
    $string_var = $row["string_name"];
    $row_id = $row["id"];

    $update_row = mysqli_query($conn, "UPDATE table_name SET string_name='$string_var' WHERE id=$row_id");
}

This step updated all the strings from the table without any hidden/problem causing character.

I am not generalising this approach and I am not sure if this will work in every use case but it helped me fix my issue in less than a minute.

I request @Uueerdo and others with better understanding on this to post a more generic approach so that it can help others because I think many people who can't find a right approach in such conditions, end up using LIKE in place of = but that completely changes the core idea of the query.

Javascript String Compare == sometimes fails

Double equals is the appropriate way to compare strings in Javascript, it is returning false then there may be whitespace to the left and or right of one string.

Put a .trim() on the end of the strings and my comparison should started working:

var panel = response.substr(0, response.indexOf("<")).trim();
if(panel == "combo"){
    //do something
}

Why doesn't my string comparison work?

Your second comparison is wrong. You should also use equals instead of ==, like this:

if (action.trim().equals("something"))

The == operator compares references of (String) objects and under normal circumstances equal strings don't automatically have the same reference, i.e. they are different objects. (Unless both are internalized, but normally you shouldn't consider it)

Other than that your example works fine and the first comparison is valid. Try fixing the second comparison. If it works, you found your problem. If not, try using a debugger and double-check everything.

PS: When comparing literal strings with dynamic string objects, it's good practice to call the equals method on the literal string:

"something".equals(action)

That way you can avoid NullPointerExceptions when the string object is null.

String comparison not working for text received from web scraping

Your html string has html entities

Dividends INR does not equal Dividends <span>INR

use https://pub.dartlang.org/packages/html_unescape to decode itemheader before you do comparison

python string comparison (==) not working

You seem to have a string processing error.
PlayerId seems to be a C-String being stored in a unicode String.

Background: C uses a nullbyte (\x00) to mark the end of a string. Since this nullbyte is in your string it ends up in the string representation of the object.

You can take a look here, for some reference. But without more code I am not sure about the cause/fix.

Have you tried type(playerId)?

edit: I don't know what python implementation you are using, for cpython look here

Unfortunately I am not to firm in interfacing c and python, however you could try to use PyString_FromString to convert it on the c side to a python string or use some handcrafted function (eg split with regex at the first unescaped 0).

Some interfacing libs are listed in this awnser

String comparison does not work in python

As it turns out, your string has new-lines (\n\n) at the end.

You can use

text = text.strip()

to remove any surrounding whitespace from your string.

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