🔧 Path.mkdir(parents, exist_ok) in Python

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Path.mkdir() can create zero or more directories as shown below:

*Memos:

• There is the 1st argument for Path() (Required-Type:str, bytes or os.PathLike). *Its argument name doesn't exist.
• The 1st argument is mode for mkdir() (Optional-Default:0o777-Type:int).
• The 2nd argument is parents for mkdir() (Optional-Default:False-Type:bool): *Memos:
  • If it's False, the path with a target directory and one or more non-existent parent directories cannot be created, getting FileNotFoundError.
  • If it's True, the path with a target directory and one or more non-existent parent directories can be created, not getting FileNotFoundError.
  • Basically, True is set to it.
• The 3rd argument is exist_ok for mkdir() (Optional-Default:False-Type:bool): *Memos:
  • If it's False, FileExistsError is raised for an existent path.
  • If it's True, FileExistsError isn't raised for an existent path.
  • Basically, True is set to it.

#     Parent directories
#         ↓↓↓↓ ↓↓↓↓↓↓
p = Path('dir3/dir3_1/dir3_1_1')
#                     ↑↑↑↑↑↑↑↑
#                 A target directory

1. Creating dir1 is successful:

from pathlib import Path

p = Path('dir1')

p.mkdir()
# Or
# p.mkdir(mode=0o777, parents=False, exist_ok=False)

# my_project
#  └-dir1 <- Here

2. Recreateing dir1 is failed and gets FileExistsError:

from pathlib import Path

p = Path('dir1')

p.mkdir()
# FileExistsError: [Errno 17] File exists: 'dir1'

# my_project
#  └-dir1

3. Recreating dir1 with exist_ok=True is failed but doesn't get FileExistsError:

from pathlib import Path

p = Path('dir1')

p.mkdir(exist_ok=True)

# my_project
#  └-dir1

4. Creating dir1_1 in dir1 is successful:

from pathlib import Path

p = Path('dir1/dir1_1')

p.mkdir()

# my_project
#  └-dir1
#     └-dir1_1 <- Here

5. Creating dir2/dir2_1 is failed and gets FileNotFoundError:

from pathlib import Path

p = Path('dir2/dir2_1')

p.mkdir()
# FileNotFoundError: [Errno 2] No such file or directory: 'dir2/dir2_1'

# my_project
#  └-dir1
#     └-dir1_1

6. Creating dir2/dir2_1 with parents=True is successful:

from pathlib import Path

p = Path('dir2/dir2_1')

p.mkdir(parents=True)

# my_project
#  |-dir1
#  |  └-dir1_1
#  └-dir2 <- Here
#     └-dir2_1 <- Here

7. Creating dir3/dir3_1/dir3_1_1 with parents=True and exist_ok=True is successful:

from pathlib import Path

p = Path('dir3/dir3_1/dir3_1_1')

p.mkdir(parents=True, exist_ok=True)

# my_project
#  |-dir1
#  |  └-dir1_1
#  |-dir2
#  |  └-dir2_1
#  └-dir3 <- Here
#     └-dir3_1 <- Here
#        └-dir3_1_1 <- Here

8. Recreating dir3/dir3_1/dir3_1_1 with parents=True and exist_ok=True is failed but doesn't get FileExistsError:

from pathlib import Path

p = Path('dir3/dir3_1/dir3_1_1')

p.mkdir(parents=True, exist_ok=True)

# my_project
#  |-dir1
#  |  └-dir1_1
#  |-dir2
#  |  └-dir2_1
#  └-dir3
#     └-dir3_1
#        └-dir3_1_1