Regular expression for a string that does not start with a sequence

You could use a negative look-ahead assertion:

^(?!tbd_).+

Or a negative look-behind assertion:

(^.{1,3}$|^.{4}(?<!tbd_).*)

Or just plain old character sets and alternations:

^([^t]|t($|[^b]|b($|[^d]|d($|[^_])))).*

Related Posts:

  1. Using or ‘|’ in regex [duplicate]
  2. What is a Context Free Grammar?
  3. What does \’.- mean in a Regular Expression
  4. How can I exclude one word with grep?
  5. How can I validate an email address using a regular expression?
  6. Regular expression to match a line that doesn’t contain a word
  7. Difference between \b and \B in regex
  8. Regex: ignore case sensitivity
  9. What does the regex \S mean in JavaScript?
  10. How can I validate an email address using a regular expression?
  11. Regex: ignore case sensitivity
  12. Python regex AttributeError: ‘NoneType’ object has no attribute ‘group’
  13. Regular Expression for alphanumeric and underscores
  14. What is the difference between the regular expressions [^\d\s] and [\D\S]
  15. Regular Expression for alphanumeric and underscores
  16. grep –ignore-case –only
  17. Regex AND operator
  18. python re.split() to split by spaces, commas, and periods, but not in cases like 1,000 or 1.50
  19. python re.split() to split by spaces, commas, and periods, but not in cases like 1,000 or 1.50
  20. Regex to test if string begins with http:// or https://
  21. Regular Expression to match string starting with a specific word
  22. Regular Expressions: Is there an AND operator?
  23. Regular expression to match standard 10 digit phone number
  24. What is a non-capturing group in regular expressions?
  25. Split string on whitespace in Python
  26. How to validate an email address in PHP
  27. What is a non-capturing group in regular expressions?
  28. Regular expression to match standard 10 digit phone number
  29. How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops
  30. Python string.replace regular expression
  31. How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops
  32. Symbol for any number of any characters in regex?
  33. Grep and Python
  34. Regex – Does not contain certain Characters
  35. Regex how to match an optional character
  36. How to validate an email address in JavaScript
  37. Using Bash regex match (=~) where regex includes quotes (” characters)
  38. Regular expression to match a word or its prefix
  39. How can I remove punctuation from input text in Java?
  40. Regular expression for exact match of a string
  41. Using the star sign in grep
  42. Regex for string contains?
  43. Question marks in regular expressions
  44. Difference between \w and \b regular expression meta characters
  45. Regular Expression – Validate Gmail addresses
  46. How can I remove punctuation from input text in Java?
  47. How can I output only captured groups with sed?
  48. How to negate specific word in regex?
  49. What is the grep equivalent in Python?
  50. javascript HTML from document.body.innerHTML
  51. Which regular expression operator means ‘Don’t’ match this character?
  52. Python re.split() vs split()
  53. How can I write a regex which matches non greedy?
  54. Regex Explanation ^.*$ [duplicate]
  55. Negative matching using grep (match lines that do not contain foo)
  56. How to replace a whole line with sed?
  57. Regex match everything after question mark?
  58. How to validate phone number using PHP?
  59. Can a URL contain a semicolon and still be valid?
  60. How is \\n and \\\n interpreted by the expanded regular expression?
  61. Regular Expression to reformat a US phone number in Javascript
  62. Regex to match only letters
  63. Finding the complement of a DFA?
  64. RegEx to find two or more consecutive chars
  65. RE error: illegal byte sequence on Mac OS X
  66. Regex to match an optional ‘+’ symbol followed by any number of digits
  67. Regex Match all characters between two strings
  68. Regular expression to match a word or its prefix
  69. Regular expressions in C: examples?
  70. How to ignore whitespace in a regular expression subject string?
  71. Regex: matching up to the first occurrence of a character
  72. Regex credit card number tests
  73. python regular expression “\1”
  74. Regular expression to stop at first match
  75. /bb|[^b]{2}/ how does it work?
  76. How do I match any character across multiple lines in a regular expression?
  77. Regular expression to remove HTML tags from a string
  78. Regular expression to limit number of characters to 10
  79. Regex that matches integers in between whitespace or start/end of string only
  80. What is the difference between square brackets and parentheses in a regex?
  81. My Vim replace with a regex is throwing a `E488: Trailing characters`
  82. Regular expression that matches valid IPv6 addresses
  83. What is the best regular expression to check if a string is a valid URL?
  84. Regex empty string or email
  85. Regex to validate date formats dd/mm/YYYY, dd-mm-YYYY, dd.mm.YYYY, dd mmm YYYY, dd-mmm-YYYY, dd/mmm/YYYY, dd.mmm.YYYY with Leap Year Support
  86. Regex difference: (\w+)? and (\w*)
  87. Wrap element with in any number of elements with PHP
  88. extract shortcodes from string
  89. preg_replace and comment_form_defaults
  90. 404 regular-expression advice needed
  91. How to use a variable as a className inside preg_match_all parameters?
  92. How to set up redirects for category paginated pages after adding /category/ to permalink
  93. Adding span tags to post titles using regex
  94. Redirect non www to www using redirection plugin regex
  95. Remove Custom HTML Posts Using Regex
  96. Regexes allow only [a-z][A-Z][0-9] and –
  97. Call Shortcode Attribute Value within another function
  98. How to fix old embeded iframes with WP-CLI search-replace
  99. Regex For Extracting First 4 letters of search term
  100. Use Regex Redirection via htsaccess for RSS Feeds WordPress

Leave a Comment