如何查找变量是否包含某些字符？ PHP [重复]

Question

This question already has an answer here:

• How do I check if a string contains a specific word? 36 answers

Intro

In search, i want to make search for age range.

if a user inserts a '-' included input like 10-30 this way i will display list of people age greater than 10 and less than 30.

My Question

$q = mysql_real_escape_string(htmlspecialchars("user input from search field"));

From here before entering to make query i want to make two conditions, One: if there's a '-' in user input or not ? if yes i want to query as according, if not the other way.

So, how can i enter into the first condition ?

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Answer 1

This will work:

// use strpos() because strstr() uses more resources
if(strpos("user input from search field", "-") === false)
{
    // not found provides a boolean false so you NEED the ===
}
else
{
    // found can mean "found at position 0", "found at position 19", etc...
}

strpos()

What NOT to do

if(!strpos("user input from search field", "-"))

The example above will screw you over because strpos() can return a 0 (zero) which is a valid string position just as it is a valid array position.

This is why it is absolutely mandatory to check for === false