After several major version upgrades, "OS X" was also renamed "macOS", and the "Disk Utility" that comes with the system has also undergone major changes in both function and interface. Mac Apple users can use Disk Utility to change the size of the disk partition at will without erasing the main partition. The editor of macw brings a detailed disk adjustment tutorial. 
Some Mac users installed Windows in order to create a BootCamp partition, but felt that the space was too small after partitioning, and did not know how to solve it.
Under normal circumstances, you can follow the following simple steps to complete partition resizing without backing up Mac system partition data, erasing (reformatting) the partition.
MacW提醒：尝试进行任何磁盘分区调整大小之前，请务必备份一下磁盘内的资料会更稳妥，以免因为你操作的不小心，造成不必要的损失。
1. Start "Applications -> Utilities (Others) -> Disk Utility"; 
2. Select the disk in the left list of "Disk Utility", do not select the partition; 
3. Click the "Partition" button; 
4. Click "- " button to delete the Windows partition, and then adjust the size of the "Primary Partition"; 
5. Re-allocate the new BootCamp (Windows) partition;
警告提示：给这个设备分区将删除储存在某些分区上的数据，且无法撤销。此分区将被抹掉：“NTFS”
6. Finally, click the "Partition" button to complete the partition size adjustment.
If you want to achieve a more perfect lossless partition, it is best to operate through the "Disk Utility" in the recovery mode of macOS.