// doTest checks that Sample picks items evenly. "n" samples are
// drawn from a list of numbers of length "space". This is repeated
// "iters" times. The number of times a particular number is drawn
// should be within "tolerance" of the expected number.
func doTest(t *testing.T, n, space, iters int, tolerance float64) {
count := make([]int, space)
for i := 0; i < iters; i++ {
s := stream.Sequence(
stream.Numbers(0, space-1),
stream.SampleWithSeed(n, int64(i)),
)
stream.ForEach(s, func(s string) {
num := -1 // Will cause panic below if Scan fails
fmt.Sscan(s, &num)
count[num]++
})
}
// Check that all counts are approximately equal.
expected := (float64(iters) * float64(n)) / float64(space)
minExpected := expected * (1.0 - tolerance)
maxExpected := expected * (1.0 + tolerance)
for i, n := range count {
if float64(n) < minExpected || float64(n) > maxExpected {
t.Errorf("%d has %d samples; expected range [%f,%f]\n",
i, n, minExpected, maxExpected)
}
}
}
func ExampleSample() {
stream.Run(
stream.Numbers(100, 200),
stream.Sample(4),
stream.WriteLines(os.Stdout),
)
// Output not checked since it is non-deterministic.
}
func ExampleCommand() {
stream.Run(
stream.Numbers(1, 100),
stream.Command("wc", "-l"),
stream.WriteLines(os.Stdout),
)
// Output:
// 100
}
func ExampleXargs() {
stream.Run(
stream.Numbers(1, 5),
stream.Xargs("echo"),
stream.WriteLines(os.Stdout),
)
// Output:
// 1 2 3 4 5
}
func ExampleForEach() {
err := stream.ForEach(stream.Numbers(1, 5), func(s string) {
fmt.Print(s)
})
if err != nil {
panic(err)
}
// Output:
// 12345
}
func ExampleLast() {
stream.Run(
stream.Numbers(1, 10),
stream.Last(2),
stream.WriteLines(os.Stdout),
)
// Output:
// 9
// 10
}
func ExampleDropFirst() {
stream.Run(
stream.Numbers(1, 10),
stream.DropFirst(8),
stream.WriteLines(os.Stdout),
)
// Output:
// 9
// 10
}
func ExampleWriteLines() {
stream.Run(
stream.Numbers(1, 3),
stream.WriteLines(os.Stdout),
)
// Output:
// 1
// 2
// 3
}
func ExampleSequence() {
stream.ForEach(stream.Sequence(
stream.Numbers(1, 25),
stream.Grep("3"),
), func(s string) { fmt.Println(s) })
// Output:
// 3
// 13
// 23
}
func ExampleIf() {
stream.Run(
stream.Numbers(1, 12),
stream.If(func(s string) bool { return len(s) > 1 }),
stream.WriteLines(os.Stdout),
)
// Output:
// 10
// 11
// 12
}
func ExampleNumbers() {
stream.Run(
stream.Numbers(2, 5),
stream.WriteLines(os.Stdout),
)
// Output:
// 2
// 3
// 4
// 5
}
func ExampleXargsFilter_LimitArgs() {
stream.Run(
stream.Numbers(1, 5),
stream.Xargs("echo").LimitArgs(2),
stream.WriteLines(os.Stdout),
)
// Output:
// 1 2
// 3 4
// 5
}
func ExampleGrepNot() {
stream.Run(
stream.Numbers(1, 12),
stream.GrepNot("^.$"),
stream.WriteLines(os.Stdout),
)
// Output:
// 10
// 11
// 12
}
func ExampleFirst() {
stream.Run(
stream.Numbers(1, 10),
stream.First(3),
stream.WriteLines(os.Stdout),
)
// Output:
// 1
// 2
// 3
}
func ExampleSampleWithSeed() {
stream.Run(
stream.Numbers(1, 100),
stream.SampleWithSeed(2, 100),
stream.Sort().Num(1),
stream.WriteLines(os.Stdout),
)
// Output:
// 11
// 46
}
func ExampleXargs_splitArguments() {
// Xargs should split the long list of arguments into
// three executions to keep command length below 4096.
stream.Run(
stream.Numbers(1, 2000),
stream.Xargs("echo"),
stream.Command("wc", "-l"),
stream.WriteLines(os.Stdout),
)
// Output:
// 3
}
func ExampleSubstitute() {
stream.Run(
stream.Numbers(1, 5),
stream.Substitute("(3)", "$1$1"),
stream.WriteLines(os.Stdout),
)
// Output:
// 1
// 2
// 33
// 4
// 5
}
func ExampleDropLast() {
stream.Run(
stream.Numbers(1, 10),
stream.DropLast(3),
stream.WriteLines(os.Stdout),
)
// Output:
// 1
// 2
// 3
// 4
// 5
// 6
// 7
}
func ExampleContents() {
out, err := stream.Contents(stream.Numbers(1, 3))
fmt.Println(out, err)
// Output:
// [1 2 3] <nil>
}