带有空格，下划线，短划线和圆点的php中的preg_match [重复]

Question

This question already has an answer here:

• How do I allow spaces in this regex? 6 answers

I am trying to match a regular expression in PHP, using the following code.

if (!preg_match("/^[a-zA-Z0-9-_.]*$/",$string)) { 
  // Show error
 }

I want to allow

• Integers (0-9)
• Characters (small letters and capital letters) (a to z and A to Z)
• Dots ( . )
• Underscore ( _ )
• Dash ( - )
• Space ( )

It does not work. Does anyone have any suggestions for what I am doing wrong?

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Answer 1

You should use:

if (!preg_match("/^[\w\s\.-]*$/",$string)) {
    #show error
}

It will also match empty string because of '*'.