This function is designed to allow users to directly edit data for a particular field, though it does not automatically take into account subfields unless specifically identified in the query. To edit subfields within a field, see Editing Subfield Data

1. Open the .mrk file by selecting it in the folder, which should open the file in MarcEditor, or open MarcEditor from the MarcEdit home screen and select the file in File->Open. 
2. Each datafield will be indicated by “=XXX” notation, which is fully searchable within MarcEditor. This allows users to perform very specific functions using regular expressions, but it is worth remembering when searching the document.
3. To find and replace data within fields in a batch of records, go to Tools > Edit Field Data, as below:

4. You should see the following dialog box:

                     
First select the field you would like to search and replace from the dropdown menu or keying it in manually. Then enter the text you would like to search or the regular expression you would like to use for the search. If “Match Case” is selected MarcEdit will be case-sensitive when performing the search. If you are searching with regular expressions, be sure “Use Regular Expressions” is checked. When you are finished, the dialog box should look something like this:

5. Click Process. MarcEdit will tell you how many modifications were made within the document. The results of the transformation I performed can be seen here: 

6. You will notice that the data was added to the field specified, not the subfield. For information on adding and editing subfields, see Editing Subfield Data

You can also enter the subfield using the $[subfieldcode] notation and MarcEdit will add it to the entered datafield.

7. To convert this edited record back into a MARC record from the Mnemonic format, you can press the icon from the toolbar shown below.

8. You will be prompted to give the compiled record a name, as the creator of MarcEdit tends to favor the creation of duplicates rather than regularly modifying the same record. 

This functionality provides a simple way to shift specific data within one datafield into another datafield or copy data from one field into another. This function allows for greater granularity in what data is moved and allows users to specify that the copied data be stored in a field with particular indicators or subfields. The Copying Field Data function above is designed primarily to move data along with subfield and indicator information into a new field, while this function is better suited to taking data from one field and putting into a field which may have different indicators or subfields.

1. Open the .mrk file by selecting it in the folder, which should open the file in MarcEditor, or open MarcEditor from the MarcEdit home screen and select the file in File > Open.
2. Select Tools > Swap Field Data
3. A dialog box should appear:

 The “Original Data” line specifies which field you would like to copy the data from while the “Modified Data” line indicates which field you would like to move or swap the data into.

When entering data for the field you would like to copy, be sure to include the indicator and subfield data. This also applies to the data field you would like to copy the data into. If this information is not entered, MarcEdit will not be able to copy the data or place it in the desired field.

4. Next select the sort settings. Below is a table outlining the general result if each box is checked:

5. When you are finished, the screen should something like this, depending on preferences:

Note that if both Find fields are left blank, it will search and swap everything in the specified fields. Use a regular expression to more precisely add data to the specified field and be sure “Treat as Regular Expression” is checked.

6. Click Process. MarcEdit will perform the specified swap. The results of the above function can be found below:  

Notice that the indicator data and subfield data are not the same as in the original field. This is the result of the particular transformation specified in the example, though it would not be possible were the Copying Field Data function instead.

7. Should you want to undo it, click Edit > Special Undo.
8. To convert this edited record back into a MARC record, select File > Compile File to MARC

This function allows you to move data from one datafield to another. It is similar to the Swap Data field, only it will simply move data from one field to another rather than switching fields in their entirety.

1. Open the .mrk file by selecting it in the folder, which should open the file in MarcEditor, or open MarcEditor from the MarcEdit home screen and select the file in File > Open.
2. Each datafield will be indicated by “=XXX” notation, which is fully searchable within MarcEditor.
3. Select Edit > Copy Field. This dialog box should appear:

The source field will be the field that the data will be copied from. Since it does not allow for you to specify subfields or indicators, it may be easier to use the Swapping Data Between Fields tool also listed on this page if you only want to move certain subfields to a new field. The Copying Field Data works well if you are simply looking to create a new field from an existing field. If there are more than one instances of a particular field and you would like to copy just one of them, utilize the “Find in Field” box to specify this field. An example of this kind of search using a regular expression can be found below: When you have entered the search data, the dialog box should look like this:

This search will find an 035 field which has the string “(OCoLC)ocm” and copy anything after that string into a 999$a field. If the “Find in Field” box were left blank, MarcEdit would create a 999$a field for each 035 field present in the record. Click Copy when you are ready.
The results of the action specified above can be seen below:

As you can see, the indicator and subfield data has been migrated to the new field as well.

4. To undo the result of this transformation, select Edit > Special Undo.
5. To compile the record back into MARC, select File > Compile File to MARC