PHP - regex to allow letters and numbers only

Question

I have tried   preg match     a-zA-Z0-9     value    but im doing something wrong i guess

User · Answer

You left off the    pattern delimiter  and    match end string    preg match     a-zA-Z0-9        value

User · Answer

1  Use PHP s inbuilt ctype alnum  You dont need to use a regex for this  PHP has an inbuilt function ctype alnum which will do this for you  and execute faster    lt  php  strings   array  AbCd1zyZ9    foo   bar    foreach   strings as  testcase        if  ctype alnum  testcase             echo  The string  testcase consists of all letters or digits  n         else           echo  The string  testcase does not consist of all letters or digits  n             gt    2  Alternatively  use a regex  If you desperately want to use a regex  you have a few options   Firstly   preg match      w        string      w includes more than alphanumeric  it includes underscore   but includes all of  d   Alternatively      a-zA-Z d       Or even just        W

User · Answer

try this way  eregi    A-Za-z0-9      value

User · Answer

As the OP said that he wants letters and numbers ONLY  no underscore    one more way to have this in php regex is to use posix expressions        alnum         Note  This will not work in Java  JavaScript  Python  Ruby   NET

User · Answer

Missing end anchor   Missing multiplier Missing end delimiter   So it should fail anyway  but if it may work  it matches against just one digit at the beginning of the string      a-z0-9    i

[php] PHP - regex to allow letters and numbers only

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