Array node
Array Stats
Full statistics: min, max, mean, median, standard deviation, variance, range. A comprehensive single-node alternative to using separate Array Min, Array Max, and Array Average nodes.
Inputs
| Port | Type |
|---|---|
| ArrayThe list of numbers to analyse — cable any array stream here, such as an EEG band, a spectrum or point components. Entries that are not numbers are skipped; an empty list reports zeros and index -1. | any |
Outputs
| Port | Type |
|---|---|
| Min | float |
| Max | float |
| Mean | float |
| Median | float |
| Sum | float |
| StdDev | float |
| Variance | float |
| Range | float |
| Count | int |
| Min Index | int |
| Max Index | int |
How It Works
Array Stats computes a comprehensive set of descriptive statistics from a numeric array in a single pass:
- Min / Max: Smallest and largest values.
- Mean: Arithmetic average (sum ÷ count).
- Median: Middle value when sorted (average of two middle values for even-length arrays).
- Sum: Total of all elements.
- StdDev: Population standard deviation — measures how spread out values are.
- Variance: StdDev² — the squared deviation.
- Range: Max − Min — the span of values.
- Min Index / Max Index: Positions of the minimum and maximum values.
Use Cases
- Data profiling: Instantly characterize any numeric dataset with a single node.
- Outlier detection: Values more than 2× StdDev from the Mean are potential outliers.
- Signal quality: Low StdDev indicates a stable signal; high StdDev indicates noise or variability.
- Normalization: Use Min and Range to normalize values to 0–1:
(value - Min) / Range. - EEG analysis: Compute statistics per channel or across channels for brain activity metrics.
Tips
- If you only need one or two statistics, individual nodes (Array Min, Array Max, Array Average) are slightly more efficient.
- StdDev uses population formula (divides by N, not N-1). For small sample sizes where you need the sample standard deviation, multiply by
√(N/(N-1)). - Median requires internal sorting, so it's slightly more expensive than Mean for very large arrays.
Open Array Stats in the interactive catalog →
Array Stats is one of 381 nodes in Grafit Pro.
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