# SubstituteStringEntry
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This object defines one log field key that will be replaced using the [ substituteString](https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/CloudWatch-Logs-Transformation.html#CloudWatch-Logs-Transformation-substituteString) processor.

## Contents
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 ** from **   <a name="CWL-Type-SubstituteStringEntry-from"></a>
The regular expression string to be replaced. Special regex characters such as [ and ] must be escaped using \$1\$1 when using double quotes and with \$1 when using single quotes. For more information, see [ Class Pattern](https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/regex/Pattern.html) on the Oracle web site.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Required: Yes

 ** source **   <a name="CWL-Type-SubstituteStringEntry-source"></a>
The key to modify  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Required: Yes

 ** to **   <a name="CWL-Type-SubstituteStringEntry-to"></a>
The string to be substituted for each match of `from`   
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Required: Yes

## See Also
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For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/logs-2014-03-28/SubstituteStringEntry) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/logs-2014-03-28/SubstituteStringEntry) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/logs-2014-03-28/SubstituteStringEntry)