How do I concatenate strings in PHP using the . operator?
Jun 22, 2025 am 12:57 AMIn PHP, use the dot (.) operator to concatenate the string. For example, echo "Hello" . "World"; output HelloWorld; you can store strings in variables and then connect them, such as $greeting = "Hello"; $name = "John"; echo $greeting . $name; output HelloJohn; if spaces or punctuation are needed, it must be added manually; you can also mix variables with text, such as $message = "Welcome, " . $name . "! Thank you for logging in."; It is recommended to pay attention to the use of quotes, reasonable addition of spaces and punctuations; you can gradually build strings in a loop, such as using $output .= "- " . $item . "
"; Common errors include misuse of plus signs ( ) and quotation nesting are not handled correctly, such as echo 'Hello $name'; will not resolve variables, it should be changed to echo 'Hello ' . $name;.
In PHP, you concatenate strings using the dot ( .
) operator. It's a straightforward way to combine two or more strings into one.
Basic Usage of the .
Operator
The main thing to know is that in PHP, the
sign doesn't work for combining text — you have to use the .
instead.
For example:
echo "Hello" . "World"; // Outputs: HelloWorld
You can also store parts of the string in variables and then join them:
$greeting = "Hello"; $name = "John"; echo $greeting . $name; // Outputs: HelloJohn
One thing to watch out for: if you don't add spaces or punctuation manually, PHP won't do it for you. So if you want a space between words, you need to include it in one of the strings or add it as a separate part.
Combining Strings with Variables and Text
A common situation is when you're building a sentence that includes both static text and dynamic values ??(like user input or database results). You can mix variables and literal strings freely.
Here's how you might build a message:
$name = "Sarah"; $message = "Welcome, " . $name . "! Thank you for logging in."; echo $message; // Outputs: Welcome, Sarah! Thank you for logging in.
This approach works well in many scenarios like generating HTML content dynamically or preparing messages to display on a webpage.
Some tips:
- Keep an eye on quotation marks — especially when mixing single and double quotes.
- Use parentshes if needed to make complex concatenation easier to read.
- Don't forget to include spaces or punctuation where necessary.
Concatenating in Larger Blocks or Loops
Sometimes you'll want to build up a string gradually — for instance, looping through an array and collecting output line by line.
Here's a basic loop example:
$items = ["apple", "banana", "cherry"]; $output = ""; foreach ($items as $item) { $output .= "- " . $item . "<br>"; } echo $output;
In this case, we start with an empty string and keep adding to it using .=
(which is short for $output = $output . "something"
).
This method is often used for:
- Building lists or tables dynamically
- Preparing email content from multiple sources
- Creating custom log entries
Make sure you initialize your variable before the loop starts, or you'll get errors.
A Couple Common Mistakes to Avoid
It's easy to make small mistakes that break your code. Here are two common ones:
- Using
.
: PHP will try to convert your strings to numbers and add them, which leads to unexpected results or even silent errors. - Mixing quotes without escaping properly: If you're inside single quotes and try to use a variable, it won't be interpreted correctly unless you close the quote or use double quotes.
Example of something that won't work:
echo 'Hello $name'; // Outputs: Hello $name, not Hello Sarah
Instead, either use double quotes or concatenate the variable:
echo 'Hello ' . $name;
Basically that's it.
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