Iterator

env.zig provides an Iterator for traversing key-value pairs with advanced operations.

Basic Iteration

Using keys()

for (env.keys()) |key| {
    try stdout.print("{s} = {s}\n", .{ key, env.get(key).? });
}

Using the Iterator

var it = env.iterator();
defer allocator.free(it.entries); // Free allocated entries
while (it.next()) |entry| {
    try stdout.print("{s} = {s}\n", .{ entry.key, entry.value });
}

WARNING

The iterator allocates an entries slice. Always free it with defer allocator.free(it.entries).

Advanced Operations

Peek

Look at the next entry without consuming it:

var it = env.iterator();
defer allocator.free(it.entries);

if (it.peek()) |entry| {
    try stdout.print("Next: {s}\n", .{entry.key});
}

// Still at the same position
if (it.peek()) |entry| {
    try stdout.print("Same: {s}\n", .{entry.key}); // Same entry
}

Skip

Skip entries ahead:

var it = env.iterator();
defer allocator.free(it.entries);
it.skip(2); // Skip first 2 entries

while (it.next()) |entry| {
    // Starts from 3rd entry
}

Reset

Return to the beginning:

var it = env.iterator();
defer allocator.free(it.entries);
_ = it.next();
_ = it.next();

it.reset(); // Back to first entry

Remaining

Check how many entries are left:

var it = env.iterator();
defer allocator.free(it.entries);
try std.testing.expectEqual(@as(usize, 5), it.remaining());

it.skip(2);
try std.testing.expectEqual(@as(usize, 3), it.remaining());

Collect

Gather entries matching a predicate:

const isDatabase = struct {
    fn predicate(entry: env_mod.Iterator.Entry) bool {
        return std.mem.startsWith(u8, entry.key, "DATABASE");
    }
}.predicate;

var it = env.iterator();
defer allocator.free(it.entries);
const db_entries = try it.collect(allocator, isDatabase);
defer allocator.free(db_entries);

for (db_entries) |entry| {
    try stdout.print("DB config: {s} = {s}\n", .{ entry.key, entry.value });
}

Entry Count

const count = env.count();
try stdout.print("Total entries: {d}\n", .{count});

See Also

• Getting Started for configuration options
• API Reference for the full API