adii1823
104 lines
2.9 KiB
Python
104 lines
2.9 KiB
Python
# sequences.py
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# strings
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>>> # 4 ways to make a string
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>>> str1 = 'This is a string. We built it with single quotes.'
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>>> str2 = "This is also a string, but built with double quotes."
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>>> str3 = '''This is built using triple quotes,
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... so it can span multiple lines.'''
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>>> str4 = """This too
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... is a multiline one
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... built with triple double-quotes."""
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>>> str4 #A
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'This too\nis a multiline one\nbuilt with triple double-quotes.'
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>>> print(str4) #B
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This too
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is a multiline one
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built with triple double-quotes.
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>>> s = 'Hello There'
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>>> s.removeprefix('Hell')
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'o There'
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>>> s.removesuffix('here')
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'Hello T'
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>>> s.removeprefix('Ooops')
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'Hello There'
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# encode / decode
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>>> s = "This is üŋíc0de" # unicode string: code points
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>>> type(s)
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<class 'str'>
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>>> encoded_s = s.encode('utf-8') # utf-8 encoded version of s
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>>> encoded_s
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b'This is \xc3\xbc\xc5\x8b\xc3\xadc0de' # result: bytes object
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>>> type(encoded_s) # another way to verify it
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<class 'bytes'>
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>>> encoded_s.decode('utf-8') # let's revert to the original
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'This is üŋíc0de'
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>>> bytes_obj = b"A bytes object" # a bytes object
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>>> type(bytes_obj)
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<class 'bytes'>
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# length
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>>> len(str1)
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49
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# indexing and slicing
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>>> s = "The trouble is you think you have time."
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>>> s[0] # indexing at position 0, which is the first char
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'T'
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>>> s[5] # indexing at position 5, which is the sixth char
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'r'
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>>> s[:4] # slicing, we specify only the stop position
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'The '
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>>> s[4:] # slicing, we specify only the start position
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'trouble is you think you have time.'
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>>> s[2:14] # slicing, both start and stop positions
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'e trouble is'
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>>> s[2:14:3] # slicing, start, stop and step (every 3 chars)
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'erb '
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>>> s[:] # quick way of making a copy
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'The trouble is you think you have time.'
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# formatting
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>>> greet_old = 'Hello %s!'
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>>> greet_old % 'Fabrizio'
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'Hello Fabrizio!'
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>>> greet_positional = 'Hello {}!'
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>>> greet_positional.format('Fabrizio')
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'Hello Fabrizio!'
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>>> greet_positional = 'Hello {} {}!'
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>>> greet_positional.format('Fabrizio', 'Romano')
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'Hello Fabrizio Romano!'
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>>> greet_positional_idx = 'This is {0}! {1} loves {0}!'
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>>> greet_positional_idx.format('Python', 'Heinrich')
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'This is Python! Heinrich loves Python!'
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>>> greet_positional_idx.format('Coffee', 'Fab')
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'This is Coffee! Fab loves Coffee!'
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>>> keyword = 'Hello, my name is {name} {last_name}'
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>>> keyword.format(name='Fabrizio', last_name='Romano')
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'Hello, my name is Fabrizio Romano'
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# formatted string literals
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>>> name = 'Fab'
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>>> age = 42
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>>> f"Hello! My name is {name} and I'm {age}"
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"Hello! My name is Fab and I'm 42"
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>>> from math import pi
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>>> f"No arguing with {pi}, it's irrational..."
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"No arguing with 3.141592653589793, it's irrational..."
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# f-string debug
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>>> user = 'heinrich'
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>>> password = 'super-secret'
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>>> f"Log in with: {user} and {password}"
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'Log in with: heinrich and super-secret'
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>>> f"Log in with: {user=} and {password=}"
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"Log in with: user='heinrich' and password='super-secret'"
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