Posted on January 6, 2023 (Updated on July 18, 2025)

How to remove underscore from filename in directory using modelbuilder

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Ditching the Underscore: A ModelBuilder Trick for Tidy Filenames

Let’s face it: messy filenames can be a real headache, especially when you’re juggling tons of GIS data. Underscores, while sometimes necessary, can clutter things up. Ever wished you could just wave a magic wand and get rid of them all in one go? Well, with ArcGIS’s ModelBuilder, you practically can! It’s like having a little robot assistant to clean up your digital workspace.

ModelBuilder is basically a visual way to string together geoprocessing tools in ArcGIS i. Think of it as a flowchart for your GIS tasks. Instead of clicking through menus over and over, you build a model once, and then let it run. It’s perfect for those repetitive jobs that make you want to pull your hair out.

So, how do we use this magic to zap those pesky underscores? Here’s the breakdown:

  • Fire up ModelBuilder: In ArcMap or ArcGIS Pro, go to Geoprocessing > ModelBuilder i. A shiny, blank canvas awaits.

  • Grab the “Iterate Files” tool: This is the workhorse that goes through all the files in your chosen folder. You’ll find it under Insert > Iterators > Files i. Drag it onto your ModelBuilder window.

  • Tell “Iterate Files” where to look: Double-click the “Iterate Files” box to open its settings. Point it to the folder holding your files. Want to be picky? Use the “Wildcard” option to only grab certain file types, like “*.shp” for shapefiles i. Leave it blank to grab everything.

  • Bring in the “Rename” tool: Search for “Rename” in the “Tools” pane and drag it in i. This is the tool that actually does the renaming.

  • Connect the dots: Now, drag a line from the “Name” output of the “Iterate Files” tool to the “Input Dataset” of the “Rename” tool i. This tells the Rename tool which files to work on.

  • The underscore-busting magic: This is where things get interesting. We need to tell the “Rename” tool how to rename the files.

    • Option 1: “Calculate Value” to the rescue: This is my preferred method. Add the “Calculate Value” tool to your model i. Connect the “Name” output from “Iterate Files” to it. Now, in the “Calculate Value” settings, you’ll write a tiny bit of Python code to remove the underscores. The expression would look something like this: “%Name%”.replace(“_”,””). Make sure you set the “Data Type” to “String”. Finally, tell the “Rename” tool to use the output of the “Calculate Value” tool for the new filename.

    • Option 2: A shortcut (maybe): In the “New Name” field of the “Rename” tool, you might be able to directly use something like “%Name:replace(_,”)%”. This should tell it to replace underscores, but sometimes it doesn’t work as expected. The “Calculate Value” method is generally more reliable.

  • Pick a spot for the renamed files: Make sure the output workspace is set correctly. This is where the renamed files will end up. It can be the same as the input folder, which means you’ll be renaming the files in place.

  • Double-check your work: Hit the “Validate” button to make sure everything is connected properly and there are no obvious errors i.

  • Let it rip!: Click “Run” and watch ModelBuilder go to work i. It’ll loop through each file, strip out the underscores, and rename the files.

    • A Few Words of Caution

    • File extensions are your friends: This process only renames the base filename, leaving the extension (like “.shp”) untouched.
    • Don’t overwrite!: Be super careful when renaming files in the same folder. If you end up with two files having the same name, you could lose data. Consider adding a counter or something to make sure each filename is unique.
    • Things go wrong: For serious models, add some error handling to deal with unexpected problems.
    • Python power: While ModelBuilder is great, Python scripting gives you even more control for complex renaming tasks. It’s worth learning if you’re doing a lot of this kind of thing.

    Real-World Example

    Let’s say you’ve got a folder full of shapefiles named like “building_parcels.shp”, “street_network.shp”, and “water_bodies.shp”. Run this ModelBuilder tool, and poof, they become “buildingparcels.shp”, “streetnetwork.shp”, and “waterbodies.shp” – nice and tidy!

    The Takeaway

    ModelBuilder is a fantastic tool for automating all sorts of GIS tasks, and removing underscores from filenames is just one example. By combining the “Iterate Files” and “Rename” tools with a little bit of Python magic, you can keep your data organized and save yourself a ton of time. Trust me, your future self will thank you!

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