TakeWhile & SkipWhile in C#

Cut a sequence at the first element that breaks the rule.

var readings = new[] { 1, 2, 4, 8, 3, 1, 9 };

// TakeWhile stops at the first failure; Where would keep going
Console.WriteLine(string.Join(",", readings.TakeWhile(r => r < 5)));
Console.WriteLine(string.Join(",", readings.Where(r => r < 5)));

// SkipWhile drops the prefix, then keeps everything after it
Console.WriteLine(string.Join(",", readings.SkipWhile(r => r < 5)));

// Take and Skip page through by count
Console.WriteLine(string.Join(",", readings.Skip(2).Take(3)));

How it works

1. TakeWhile stops at the first failure; Where would keep filtering.
2. SkipWhile drops the prefix and keeps everything after it.
3. Skip(2).Take(3) pages by count instead of by condition.

Keywords and builtins used here

• new
• string
• var

The run, in numbers

Lines

11

Characters to type

479

Tokens

118

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 79 seconds.

Type this snippet

Step 1 of 3 in Slicing, step 4 of 17 in LINQ in depth.

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