```
length(diag(4)) # = 16 (4 x 4)
length(options()) # 12 or more
length(y ~ x1 + x2 + x3) # 3
length(expression(x, {y <- x^2; y+2}, x^y)) # 3
## from example(warpbreaks)
require(stats)
fm1 <- lm(breaks ~ wool * tension, data = warpbreaks)
length(fm1$call) # 3, lm() and two arguments.
length(formula(fm1)) # 3, ~ lhs rhs
```

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