# Trajectories¶

>>> import mdtraj as md


The function mdtraj.load() will automatically detect the appropriate format based on the filename extension. The supported formats are all listed below in the format-specific loaders. The return value of mdtraj.load() is an mdtraj.Trajectory object.

While mdtraj.load() will read an entire trajectory into memory, other functions like mdtraj.load() and mdtraj.open() are available for working with trajectories in chunks, without loading them entirely into memory all at once.

## The trajectory object¶

 Trajectory(xyz, topology[, time, ...]) Container object for a molecular dynamics trajectory Topology() Topology stores the topological information about a system.