def get_label(pdb, label_df):
    """
    searches for pdb's rmsd in combined rmsd df
    :param pdb: (string) {target}_lig{id}
    :param label_df: (df) combined rmsd df
    :return: (float) rmsd value
    """
    return label_df[label_df['target'] == pdb]['rmsd'].iloc[0]