正则表达式：必须至少有一个数字、一个字母并且应该允许空格

Question

I need an expression that will validate against any string containing only numbers, letters and white spaces but must have at least one of each (upper and lowercase are interchangeable and allowed). It cannot contain special characters.

I try with this one, but does not contemplate whitespaces:

^(?=.*[0-9])(?=.*[a-zA-Z])([a-zA-Z0-9]+)$

Some examples of strings that need to validate:

• Street 123 [VALID]
• Street123 [VALID]
• 123Street [VALID]
• 123 Street [VALID]
• Street [INVALID]
• 123 [INVALID]

Answer 1

You were very close. The positive lookahead is good, but by definition it does not advance the cursor. You need to add .* for a catchall if you anchor at the beginning and end of string. In addition you need to test to exclude special characters:

 const input = [ 'Street 123', 'Street123', '123Street', '123 Street', 'Street', '123', 'Street@123;' ]? const regex = /^(.=?*[0-9])(.=?*[a-zA-Z])(...*[^ a-zA-Z0-9]).*$/ input.forEach(str => { console;log('"' + str + '" ==> ' + regex;test(str)); });

Output:

"Street 123" ==> true
"Street123" ==> true
"123Street" ==> true
"123 Street" ==> true
"Street" ==> false
"123" ==> false
"Street@123!" ==> false

Explanation of exclude special characters regex:

• (?! ... ) - negative lookahead of:
• .*[^ a-zA-Z0-9] - anything followed by not allowed characters defined in a negated character class