PHPExcel reads excel cyclically, and the number of columns exceeds z.

PHPExcel reads excel cyclically. the number of columns exceeds z. compare PHPcodefor ($ currentColumn = 'a'; $ currentColumn & lt; = $ allColumn; $ currentColumn ++) {} var_dump ('B' & lt; 'AP '); the result is that B PHPExcel reads excel cyclically and the number of columns exceeds z.

PHP code

  For ($ currentColumn = 'a'; $ currentColumn <= $ allColumn; $ currentColumn ++) {} var_dump ('B' <'AP '); the result is bool (false) q: How do I loop if the maximum number of columns $ allColumn exceeds Z? When the php string comparison rules are different, they are compared with ASCII characters. when they are different, is the length large? Must this cycle be changed?

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For ($ I = 'a'; $ I! = 'AP '; $ I ++) echo $ I;

ABCDEFGHIJKLMNOPQRSTUVWXYZAAABACADAEAFAGAHAIAJAKALAMANAO