Thanks but your code doesnt print anything on this data 

__DATA__
M7    Q    P
M54    M7    Pl
M213    M54    E
M206    M54    E
M194    M54    E
M53    M7    Pl
M186    M53    Pl
M194    M53    Pl
M187    M53    E
M204    M53    E
M201    M53    E
M202    M53    E
M179    M53    E
M13    M53    E
M157    M53    E
M173    M53    E
M205    M53    E
M195    M53    E
M196    M53    E
M197    M53    E
M198    M53    E
M57    M7    E
M44    M7    E
M61    M7    E
M13    M7    E
M50    M7    E
M158    M50    P
M157    M50    P
M153    M50    Pl
M162    M50    E
M164    M50    E
M165    M50    E
M147    M50    E
M159    M50    E

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In reply to Re^2: find shortest path for each query from a CSV file by zing
in thread find shortest path for each query from a CSV file by zing

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