Conditional Replace Rule

Want to replace N characters before or after a specific symbol based on its position? Regular find-replace can't do it, but conditional replace can.

This Feature Helps You

• Replace N characters before anchor: photo_20241225.jpg - want to change the 5 characters before _ to pic, becoming pic_20241225.jpg
• Replace N characters after anchor: report_draft_v3.docx - want to change the 1 character after _v to final, becoming report_draft_vfinal.docx
• Delete all content before anchor: [Repost]Original Article Title.txt - want to delete everything before ] (including ]), keeping only the title
• Delete all content after anchor: Product_Intro_Internal_Confidential.pptx - want to delete everything after the first _, keeping only Product_Intro

Conditional Replace vs Find Replace

Core Difference: Find-replace only changes fixed text, conditional replace uses a symbol as anchor to change specified number of characters before/after it (regardless of what those characters are).

Quick Start (3 Steps)

1. Click "Add Rule" button → Select "Conditional Replace"
2. Set three key items:
   • Target Character: Symbol to use as anchor, like _, -, ]
   • Mode: Choose to replace content before or after anchor
   • Replacement: What to change it to (leave empty to delete)
3. Preview first, confirm it's correct before applying

Detailed Examples

Example 1: Replace Specified Characters Before Anchor

❌ Original: photo_20241225.jpg, image_20241226.jpg, pic_20241227.jpg 😫 Problem: Prefixes before _ have different lengths (5, 5, 3 characters), but all want to be changed to img

✅ Operation:

• Target Character: _
• Replacement: img
• Mode: Before all characters
• Match: First

✅ Result: img_20241225.jpg, img_20241226.jpg, img_20241227.jpg

Why this setup: Using _ as anchor, replace all content before it with img. No matter what the original prefix is or how long, it's handled uniformly.

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Example 2: Delete Specified Characters After Anchor

❌ Original: document_v1.pdf, report_v2.pdf, summary_v3.pdf 😫 Problem: Want to change version numbers v1, v2, v3 to final, but version numbers aren't fixed

✅ Operation:

• Target Character: _v
• Replacement: _final
• Mode: After N characters
• Character Count: 1
• Replace Target String: Checked

✅ Result: document_final.pdf, report_final.pdf, summary_final.pdf

Why this setup: Using _v as anchor, replace the 1 character after it (version number), and check "Replace Target String" to also replace _v with _final.

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Example 3: Delete All Content After Anchor

❌ Original: Product_Plan_Internal_Discussion_Confidential.pptx, Meeting_Notes_Reference_Only_20241225.docx 😫 Problem: Want to keep only the topic name before the first _, don't need the notes after

✅ Operation:

• Target Character: _
• Replacement: (leave empty)
• Mode: After all characters
• Match: First
• Replace Target String: Checked

✅ Result: Product_Plan.pptx, Meeting_Notes.docx

Why this setup: Using the first _ as anchor, delete it and everything after it. No matter how many _ or how long the notes are, they'll all be cleaned up.

Parameters to Fill

Basic Settings

• Target Character Character or string to use as anchor, like _, -, [, _v (Can't be empty, otherwise nothing will change)

• Replacement What to replace with, like img, final (Leave empty = delete)

Advanced Options (Don't need to touch, defaults work fine)

• Mode Default is "Before N Characters". Determines which part to replace relative to target character:

  • Before N Characters (default): Replace specified number of characters before target
  • After N Characters: Replace specified number of characters after target
  • Before All Characters: Replace all content before target
  • After All Characters: Replace all content after target

• Character Count When "Before N Characters" or "After N Characters" is selected, specify how many characters to replace here. Default is 1.

• Match Default is "First", only processes the first occurrence of target character. If target character appears multiple times in filename:

  • First (default): Only process the first one
  • Last: Only process the last one
  • All: Process all matches

• Replace Target String Default unchecked, keeps the target character itself, only replaces content before/after it. When checked, will replace the target character together.

• Ignore Extension Default checked, only changes filename, doesn't touch suffixes like .pdf, .docx.

Common Questions

❓ When to use conditional replace vs find replace?

• Content to replace is fixed (like changing all IMG to Photo) → Use find replace
• Content to replace isn't fixed, but position relative to a symbol is fixed (like content before _) → Use conditional replace

❓ What happens if target character isn't found?

Filename stays unchanged, rule skips files without the target character.

❓ What if I set N characters but there aren't N characters?

Rule processes up to the filename boundary without errors. For example, if set to "after 3 characters" but there are only 2 characters after anchor, it will only replace those 2.

❓ What's "Replace Target String" for?

Controls whether to replace the target character (anchor) together.

• Unchecked (default): 2024_data.txt, target _, replace 年, mode "before all characters" → 年_data.txt (keeps _)
• Checked: Same settings → 年data.txt (_ also replaced)

Advanced Tips

• ✅ Combine with "Find Replace": First use find replace to standardize format, then use conditional replace for position-based precise processing
• ✅ Combine with "Remove Text": Conditional replace handles "relative to a symbol" deletion, remove text handles "fixed position" deletion
• ✅ Use regex for complex scenarios: If you need "only change numbers" or more complex pattern matching, consider using Regular Expression

What to Check Out Next?

• Find Replace: Simple way to replace fixed text
• Remove Text: Delete content by fixed position
• Regular Expression: More flexible pattern matching and replacement