MQL5 ReferenceStandard LibraryStringsCStringToLower StrLenCopyFillAssignAppendInsertCompareCompareNoCaseLeftRightMidTrimTrimLeftTrimRightClearToUpperToLowerReverseFindFindRevRemoveReplace ToLower Converts all string characters to lowercase. bool ToLower() Return Value true - successful, false - cannot convert to lowercase. ToUpper Reverse