$re = '/(Data\": )\"/';
$str = 'Event 1 :
=========
Input Event : [so much data exists in the same single line ] ,\\"Comments\\": \\"New alert\\", "Data": "{\\"etype\\":\\"MalwareFamily\\",\\"at\\":\\"2024-06-21T11:34:07.0000000Z\\",\\"md\\":\\"2024-06-21T11:34:07.0000000Z\\",\\"Investigations\\":[{\\"$id\\":\\"1\\",\\"Id\\":\\"urn:ZappedUrlInvestigation:2cc87ae3\\",\\"InvestigationStatus\\":\\"Running\\"}],\\"InvestigationIds\\":[\\"urn:ZappedUrlInvestigation:2cc8782d063\\"],\\"Intent\\":\\"Probing\\",\\"ResourceIdentifiers\\":[{\\"$id\\":\\"2\\",\\"AadTenantId\\":\\"2dfb29-729c918\\",\\"Type\\":\\"AAD\\"}],\\"AzureResourceId\\":null,\\"WorkspaceId\\":null,\\"Metadata\\":{\\"CustomApps\\":null,\\"GenericInfo\\":null},\\"Entities\\":[{\\"$id\\":\\"3\\",\\"MailboxPrimaryAddress\\":\\"abc@gmail.com\\",\\"Upn\\":\\"abc@gmail.com\\",\\"AadId\\":\\"6eac3b76357\\",\\"RiskLevel\\":\\"None\\",\\"Type\\":\\"mailbox\\",\\"Urn\\":\\"urn:UserEntity:10338af2b6c\\",\\"Source\\":\\"TP\\",\\"FirstSeen\\":\\"0001-01-01T00:00:00\\"}, \\"StartTimeUtc\\": \\"2024-06-21T10:12:37\\", \\"Status\\": \\"Investigation Started\\"}","EntityType": "MalwareFamily", [so much data exists in the same single line ]
Event 2 :
=======
[so much data exists in the same single line ] ,\\"Comments\\": \\"New alert\\", "Data": "{\\"etype\\":\\"MalwareFamily\\",\\"at\\":\\"2024-06-21T11:34:07.0000000Z\\",\\"md\\":\\"2024-06-21T11:34:07.0000000Z\\",\\"Investigations\\":[{\\"$id\\":\\"1\\",\\"Id\\":\\"urn:ZappedUrlInvestigation:2cc87ae3\\",\\"InvestigationStatus\\":\\"Running\\"}],\\"InvestigationIds\\":[\\"urn:ZappedUrlInvestigation:2cc8782d063\\"],\\"Intent\\":\\"Probing\\",\\"ResourceIdentifiers\\":[{\\"$id\\":\\"2\\",\\"AadTenantId\\":\\"2dfb29-729c918\\",\\"Type\\":\\"AAD\\"}],\\"AzureResourceId\\":null,\\"WorkspaceId\\":null,\\"Metadata\\":{\\"CustomApps\\":null,\\"GenericInfo\\":null},\\"Entities\\":[{\\"$id\\":\\"3\\",\\"MailboxPrimaryAddress\\":\\"abc@gmail.com\\",\\"Upn\\":\\"abc@gmail.com\\",\\"AadId\\":\\"6eac3b76357\\",\\"RiskLevel\\":\\"None\\",\\"Type\\":\\"mailbox\\",\\"Urn\\":\\"urn:UserEntity:10338af2b6c\\",\\"Source\\":\\"TP\\",\\"FirstSeen\\":\\"0001-01-01T00:00:00\\"}, \\"StartTimeUtc\\": \\"2024-06-21T10:12:37\\", \\"Status\\": \\"Investigation Started\\"}","ids": [9654,"78b3"], [so much data exists in the same single line ]
Event 3 :
==========
[so much data exists in the same single line ] ,\\"Comments\\": \\"New alert\\", "Data": "{\\"etype\\":\\"MalwareFamily\\",\\"at\\":\\"2024-06-21T11:34:07.0000000Z\\",\\"md\\":\\"2024-06-21T11:34:07.0000000Z\\",\\"Investigations\\":[{\\"$id\\":\\"1\\",\\"Id\\":\\"urn:ZappedUrlInvestigation:2cc87ae3\\",\\"InvestigationStatus\\":\\"Running\\"}],\\"InvestigationIds\\":[\\"urn:ZappedUrlInvestigation:2cc8782d063\\"],\\"Intent\\":\\"Probing\\",\\"ResourceIdentifiers\\":[{\\"$id\\":\\"2\\",\\"AadTenantId\\":\\"2dfb29-729c918\\",\\"Type\\":\\"AAD\\"}],\\"AzureResourceId\\":null,\\"WorkspaceId\\":null,\\"Metadata\\":{\\"CustomApps\\":null,\\"GenericInfo\\":null},\\"Entities\\":[{\\"$id\\":\\"3\\",\\"MailboxPrimaryAddress\\":\\"abc@gmail.com\\",\\"Upn\\":\\"abc@gmail.com\\",\\"AadId\\":\\"6eac3b76357\\",\\"RiskLevel\\":\\"None\\",\\"Type\\":\\"mailbox\\",\\"Urn\\":\\"urn:UserEntity:10338af2b6c\\",\\"Source\\":\\"TP\\",\\"FirstSeen\\":\\"0001-01-01T00:00:00\\"}, \\"StartTimeUtc\\": \\"2024-06-21T10:12:37\\", \\"Status\\": \\"Investigation Started\\"}","Name": "Phishing Categroy", [so much data exists in the same single line ]
======
';
$subst = "$1[";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php