partition in Python
*Memos:
- My post explains split() with a string and byte string.
- My post explains rsplit() with a string and byte string.
- My post explains splitlines() with a string and byte string.
- My post explains rpartition() with a string and byte string.
- My post explains encode() and decode() with a string and byte string.
- My post explains a string.
str.partition() and bytes.partition() or bytearray.partition() can split a string and byte string respectively at the 1st occurrence of a separator, searching from the left to the right as shown below:
*Memos:
- The 1st argument is
sep(Required-Type:strforstr.partition()or bytes-like object forbytes.partition()andbytearray.partition()):- It’s the separator of the one or more characters to separate a string or byte string.
- An empty string or byte string cannot be set.
- Don’t use
sep=.
- It returns a tuple of 3 elements.
- If
sepisn’t found, a tuple of the original string or byte string itself and two empty strings or byte strings in order is returned as 3 elements.
<String>:
v = "It's very very good"
print(v.partition('er'))
# ("It's v", 'er', 'y very good')
print(v.partition('very'))
# ("It's ", 'very', ' very good')
# ↓
print(v.partition(' '))
# ("It's", ' ', 'very very good')
# ↓↓
print(v.partition(' '))
print(v.partition('ER'))
print(v.partition('VERY'))
print(v.partition('really'))
# ("It's very very good", '', '')
print(v.partition(''))
# ValueError: empty separator
v = ''
print(v.partition('er'))
# ('', '', '')
<Byte String(UTF-8)>:
bytes():
v = "It's very very good".encode()
v = b"It's very very good"
print(v.partition('er'.encode()))
print(v.partition(b'er'))
# (b"It's v", b'er', b'y very good')
print(v.partition(bytearray('er'.encode())))
# (b"It's v", bytearray(b'er'), b'y very good')
print(v.partition('very'.encode()))
print(v.partition(b'very'))
# (b"It's ", b'very', b' very good')
print(v.partition(bytearray('very'.encode())))
# (b"It's ", bytearray(b'very'), b' very good')
# ↓
print(v.partition(' '.encode()))
print(v.partition(b' '))
# (b"It's", b' ', b'very very good')
print(v.partition(bytearray(' '.encode())))
# (b"It's", bytearray(b' '), b'very very good')
# ↓↓
print(v.partition(' '.encode()))
print(v.partition(b' '))
print(v.partition(bytearray(' '.encode())))
print(v.partition('ER'.encode()))
print(v.partition(b'ER'))
print(v.partition(bytearray('ER'.encode())))
print(v.partition('VERY'.encode()))
print(v.partition(b'VERY'))
print(v.partition(bytearray('VERY'.encode())))
print(v.partition('really'.encode()))
print(v.partition(b'really'))
print(v.partition(bytearray('really'.encode())))
# ("It's very very good", '', '')
print(v.partition(''.encode()))
print(v.partition(b''))
print(v.partition(bytearray(''.encode())))
# ValueError: empty separator
v = ''.encode()
v = b''
print(v.partition('er'.encode()))
print(v.partition(b'er'))
print(v.partition(bytearray('er'.encode())))
# (b'', b'', b'')
bytearray():
v = bytearray("It's very very good".encode())
print(v.partition('er'.encode()))
print(v.partition(b'er'))
print(v.partition(bytearray('er'.encode())))
# (bytearray(b"It's v"), bytearray(b'er'), bytearray(b'y very good'))
print(v.partition('very'.encode()))
print(v.partition(b'very'))
print(v.partition(bytearray('very'.encode())))
# (bytearray(b"It's "), bytearray(b'very'), bytearray(b' very good'))
# ↓
print(v.partition(' '.encode()))
print(v.partition(b' '))
print(v.partition(bytearray(' '.encode())))
# (bytearray(b"It's"), bytearray(b' '), bytearray(b'very very good'))
# ↓↓
print(v.partition(' '.encode()))
print(v.partition(b' '))
print(v.partition(bytearray(' '.encode())))
print(v.partition('ER'.encode()))
print(v.partition(b'ER'))
print(v.partition(bytearray('ER'.encode())))
print(v.partition('VERY'.encode()))
print(v.partition(b'VERY'))
print(v.partition(bytearray('VERY'.encode())))
print(v.partition('really'.encode()))
print(v.partition(b'really'))
print(v.partition(bytearray('really'.encode())))
# (bytearray(b"It's very very good"), bytearray(b''), bytearray(b''))
print(v.partition(''.encode()))
print(v.partition(b''))
print(v.partition(bytearray(''.encode())))
# ValueError: empty separator
v = bytearray(''.encode())
print(v.partition('er'.encode()))
print(v.partition(b'er'))
print(v.partition(bytearray('er'.encode())))
# (bytearray(b''), bytearray(b''), bytearray(b''))
