How can I link Analysis System Index in Mechanical to it's corresponding System Index on the Project

I don't think there is a direct link between the SYS- and Analysis index from an analysis in Mechanical, because SYS - IDs increment by 1 each time a system is created, SYS- are given to systems in the order of their creation time (SYS, SYS-1, SYS-2…), but the indexes start from zero for every Mechanical session (as shown in the screenshot). One can however, use the result file path to build a workaround.

The following code will give a dictionary - SYSTEM_ANALYSIS_LINK_DICT, which contains the mapping of SYS-ID with the analysis index.

Note: Please change "file.rst" in the regex expression as per analysis type.

SYSTEM_ANALYSIS_LINK_DICT = {}
import re
my_regex_expression = r"(.*)\MECH\file.rst"

for index, analysis in enumerate(ExtAPI.DataModel.AnalysisList):
    system_directory = re.search(my_regex_expression, analysis.Solution.ResultFilePath)
    system_string = system_directory.group(1).Split("\")[-1]
    SYSTEM_ANALYSIS_LINK_DICT.update({system_string: index})