Remove special characters, keep letters and digits
Coding problemEasyAsked in: Infosys
Given a string s, remove every character that is not an English letter (a to z, A to Z) or a digit (0 to 9). Return what is left, in the original order.
Spaces and punctuation are removed too. Interviewers often ask for this without regular expressions (short patterns that match text), so walk the characters yourself.
Examples
Example 1
Input: s = "Hello, World! 123"
Output: "HelloWorld123"
Example 2
Input: s = "user.name+qa@test.com"
Output: "usernameqatestcom"
Example 3
Input: s = "!!!"
Output: ""
Constraints
- The length of s is between 0 and 100,000
- s holds printable ASCII characters only
Run checks the 3 examples. Submit also runs the hidden tests: edge cases, large inputs and a time limit.
Run your code to see the results here. Ctrl or Cmd + Enter runs; add Shift to submit.