String in Python (6)

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*Memos:

• My post explains a string.

find() can find the 1st substring of a string, searching from the left to the right to return the index (without error even if the substring isn't found) as shown below:

*Memos:

• The 1st argument is sub(Required-Type:str): *Memos:
  • It's the substring of zero or more characters.
  • Don't use sub=.
• The 2nd argument is start(Optional-Type:int or NoneType): *Memos:
  • If it's not set or None, 0 is set.
  • Don't use start.
• The 3rd argument is end(Optional-Type:int or NoneType): *Memos:
  • If it's not set or None, the length + 1 is set.
  • Don't use end.
• -1 is returned if the substring isn't found.

v = 'grapes peach' print(v.find('pe')) # 3 print(v.find('pe', None, None)) # 3 print(v.find('PE')) # -1 print(v.find('pe', 3)) # 3 print(v.find('pe', 4)) # 7 print(v.find('pe', 7)) # 7 print(v.find('pe', 8)) # -1 print(v.find('pe', 0, 4)) # -1 print(v.find('pe', 0, 5)) # 3 print(v.find('pe', 7, 12)) # 7 print(v.find('pe', 8, 12)) # -1  print(v.find('')) # 0 print(v.find('g', 0, 1)) # 0 print(v.find('h', 11, 12)) # 1 print(v.find('abc')) # -1 

v = '' print(v.find('')) # 0 

rfind() can find the 1st substring of a string, searching from the right to the left to return the index (without error even if the substring isn't found) as shown below:

*Memos:

• The 1st argument is sub(Required-Type:str): *Memos:
  • It's the substring of zero or more characters.
  • Don't use sub=.
• The 2nd argument is start(Optional-Type:int or NoneType): *Memos:
  • If it's not set or None, 0 is set.
  • Don't use start.
• The 3rd argument is end(Optional-Type:int or NoneType): *Memos:
  • If it's not set or None, the length + 1 is set.
  • Don't use end.
• -1 is returned if the substring isn't found.

v = 'grapes peach' print(v.rfind('pe')) # 7 print(v.rfind('pe', None, None)) # 7 print(v.rfind('PE')) # -1 print(v.rfind('pe', 3)) # 7 print(v.rfind('pe', 4)) # 7 print(v.rfind('pe', 7)) # 7 print(v.rfind('pe', 8)) # -1 print(v.rfind('pe', 0, 4)) # -1 print(v.rfind('pe', 0, 5)) # 3 print(v.rfind('pe', 7, 12)) # 7 print(v.rfind('pe', 8, 12)) # -1  print(v.rfind('')) # 12 print(v.rfind('g', 0, 1)) # 0 print(v.rfind('h', 11, 12)) # 11 print(v.rfind('abc')) # -1 

v = '' print(v.rfind('')) # 0 

index() can find the 1st substring of a string, searching from the left to the right to return the index (with error if the substring isn't found) as shown below:

*Memos:

• The 1st argument is sub(Required-Type:str): *Memos:
  • It's the substring of zero or more characters.
  • Don't use sub=.
• The 2nd argument is start(Optional-Type:int or NoneType): *Memos:
  • If it's not set or None, 0 is set.
  • Don't use start.
• The 3rd argument is end(Optional-Type:int or NoneType): *Memos:
  • If it's not set or None, the length + 1 is set.
  • Don't use end.
• Error occurs if the substring isn't found.

v = 'grapes peach' print(v.index('pe')) # 3 print(v.index('pe', None, None)) # 3 print(v.index('pe', 3)) # 3 print(v.index('pe', 4)) # 7 print(v.index('pe', 7)) # 7 print(v.index('pe', 0, 5)) # 3 print(v.index('pe', 7, 12)) # 7  print(v.index('')) # 0 print(v.index('g', 0, 1)) # 0 print(v.index('h', 11, 12)) # 11  print(v.index('PE')) print(v.index('pe', 8)) print(v.index('pe', 0, 4)) print(v.index('pe', 8, 12)) print(v.index('abc')) # ValueError: substring not found 

v = '' print(v.index('')) # 0 

rindex() can find the 1st substring of a string, searching from the right to the left to return the index (with error if the substring isn't found) as shown below:

*Memos:

• The 1st argument is sub(Required-Type:str): *Memos:
  • It's the substring of zero or more characters.
  • Don't use sub=.
• The 2nd argument is start(Optional-Type:int or NoneType): *Memos:
  • If it's not set or None, 0 is set.
  • Don't use start.
• The 3rd argument is end(Optional-Type:int or NoneType): *Memos:
  • If it's not set or None, the length + 1 is set.
  • Don't use end.
• Error occurs if the substring isn't found.

v = 'grapes peach' print(v.rindex('pe')) # 7 print(v.rindex('pe', None, None)) # 7 print(v.rindex('pe', 3)) # 7 print(v.rindex('pe', 7)) # 7 print(v.rindex('pe', 0, 5)) # 3 print(v.rindex('pe', 7, 12)) # 7  print(v.rindex('')) # 12 print(v.rindex('g', 0, 1)) # 0 print(v.rindex('h', 11, 12)) # 11  print(v.rindex('PE')) print(v.rindex('pe', 8)) print(v.rindex('pe', 0, 4)) print(v.rindex('pe', 8, 12)) print(v.rindex('abc')) # ValueError: substring not found 

v = '' print(v.rindex('')) # 0