Java regex for finding combo of { and number [duplicate]

Question

I have a file with following information

Hi my {4 name is {4: Jeremy I {4: work in {4 Texas My job is {3 very {0 hard, I work until 4

I need to match all {4 values in this text, so I tried to write following regex: [\{4^:]

But when I try this on a regex tester, it matches all occurances of {, 4 and : but I only want the combination of {4 without a : in it.

What am I doing wrong?

All 4 occurrences? If you need to match {4 not followed with :, use String res = s.replaceAll("\\{4(?!:)", "newValue");. If you need to replace all {4, just use .replace("{4", "NEW_VALUE") - no need for a regex. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented May 24, 2017 at 6:27
what do you mean ...to match all {4, you dont need regex for that... — ΦXocę 웃 Пepeúpa ツ
– ΦXocę 웃 Пepeúpa ツ, Commented May 24, 2017 at 6:27

Raman Sahasi · Accepted Answer · 2017-05-24 06:38:43Z

1

Use negative lookahead to remove {4 which are followed by :. Also remove square brackets as they will match all of the results individually.

{4(?!:)

{4 matches the characters {4 literally
(?!:) is negative lookahead which means look for {4 which are not followed by :

answered May 24, 2017 at 6:32

Raman Sahasi

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