Regular expressions for password validation

I need to validate a password that matches the following criteria:

• minimum 8 characters
• contain a combination of numbers and letters
• must not enforce special characters

The follow regular expression is what I came up with:

^{8,}.(?=*\d)(?=.*[a-zA-Z])&

but this is failing on:

• !password1
• password1
• Password1

From what I can gather, trying to investigate RegEx, {8,} means minimum of 8 and don't care about the maximum, \d specifies digits, whitespaces and special characters. The a-z make开发者_C百科s sense.

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Try:

^(?=.*\d)(?=.*[a-zA-Z]).{8,}$

See it @work

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simple not most efficient way:

^[a-zA-Z0-9!.-_]{8,}$

Replace !.-_ with the list of special characters you'd like to allow