Slice ASCII Data
Extract a substring by start position and length. Runs entirely in your browser, so your data never leaves your device.
0 chars · 0 lines
Output
The result appears here as you type.
How to use Slice ASCII Data
- 1. Paste the source text. Put the full string in the input pane; it can be a single line or a large blob copied from a log or export. The slice is computed live as you adjust the numbers.
- 2. Set the Start index. Start index is zero-based, so 0 means the very first character and 2 skips the first two. In the example, slicing 'abcdef' from index 2 yields 'cdef'.
- 3. Choose a Length. Length caps how many characters the slice keeps; setting it to 0 means run to the end of the input. Use a positive value to lift an exact-width field out of the middle.
- 4. Copy the extracted substring. The output pane shows just the selected span. Copy it out, then adjust Start index or Length to walk through neighboring fields of the same record without re-pasting.
When to use Slice ASCII Data
Slice ASCII Data pulls a substring out of text by numeric position instead of by pattern. When you know a value lives at offset 40 with a width of 12, position-based extraction beats crafting a regex. It is the browser equivalent of a spreadsheet MID() or Python's s[start:start+len].
- Extracting fields from fixed-width records. A bank or mainframe export packs each row into fixed columns with no delimiters. Given the record layout, set the documented offset and width to lift out the account number or amount.
- Isolating a segment of a long identifier. A composite key embeds a date in positions 4 through 11. Slice exactly that window from a few sample IDs to confirm the embedded format before writing parsing code.
- Prototyping substring logic before coding. You are about to write a parser and want to sanity-check offsets against real data. Experiment interactively with Start index and Length here, then transcribe the working numbers into your code.
- Trimming context out of a log line. Only the middle portion of a long log entry matters for a ticket. Slice out the relevant span by position so the pasted evidence stays short and pointed.
Examples
From index 2
Input
abcdef
Output
cdef
About the Slice ASCII Data tool
Slice ASCII Data is a free online tool that works entirely inside your web browser. Extract a substring by start position and length. Because the processing happens on your own device, nothing you enter is uploaded, logged or stored anywhere.
This page is one of 81 ASCII utilities on EditSafely. Each one does a single job well, and all of them follow the same rule: your input stays on your machine.
You can shape the output with 2 settings, including Start index and Length (0 = to end), and the result refreshes the moment you change one. A worked example further down the page shows exactly what the tool produces for a real input.
Because nothing leaves your device, the tool is suitable for sensitive content such as internal documents, credentials or customer data. It also responds instantly, since every keystroke is handled on your own machine rather than by a remote API.
Frequently asked questions
Does Slice ASCII Data cost anything?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
No data leaves your device. The whole tool is JavaScript that runs inside your browser tab, so there is no upload, no server-side processing and no log of what you did. If you disconnect from the internet after the page loads, it keeps working.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
Nothing to install and no account needed. Open the page in any up-to-date browser, including on a phone or tablet, and the tool is ready.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.