there are characters like '' that are not visible so I cant copy paste it. I want to convert any character to its codepoint like '\u200D'
another example is: 'abc' => '\u0061\u0062\u0063'
Allow me to rephrase your question. The header convert a string to its codepoint in python clearly did not get through to everyone, mostly, I think, because we can't imagine what you want it for.
What you want is a string containing a representation of Unicode escapes.
You can do that this way:
print(''.join("\\u{:04x}".format(b) for b in b'abc'))
\u0061\u0062\u0063
If you display that printed value as a string literal you will see doubled backslashes, because backslashes have to be escaped in a Python string. So it will look like this:
'\\u0061\\u0062\\u0063'
The reason for that is that if you simply put unescaped backslashes in your string literal, like this:
a = "\u0061\u0062\u0063"
when you display a at the prompt you will get:
>>> a
'abc'
'\u0061\u0062\u0063'.encode('utf-8') will encode the text to Unicode.
Edit:
Since python automatically converts the string to Unicode you can't see the value but you can create a function that will generate that.
def get_string_unicode(string_to_convert):
res = ''
for letter in string_to_convert:
res += '\\u' + (hex(ord(letter))[2:]).zfill(4)
return res
Result:
>>> get_string_unicode('abc')
'\\u0061\\u0062\\u0063'
I am new to Python and I am working to calculate checksum of a string that has backslashes (). I was able to come up with a logic to calculate the checksum but that function needs the string to be in raw format (r') to calculate the correct checksum. However this function will be invoked by another function and I will not be able to convert the string to raw string manually. Can someone please help me on how to achieve this dynamically.
Here is the string:
raw_message1 = '=K+8\\\08|'
This string has 3 backslashes however it shows only 2 after saving and this string may vary again so replacing after processing will not help.
And when I print the result:
print(message1)
=K+8\ 8|
What I need is to have something that retains the backslashes as is. I cannot go for any other character as every character has its own ASCII value and checksum would differ. I tried all the other options mentioned before and see different result for each case.
You can define the string as so:
message1 = r'=K+8\\08|'
This should make the string message1 be in raw form.
Let me know if this helps. I don't really understand what you mean by converting to raw string manually and converting it dynamically. This is the most I can help with for now.
All the r prefix does is manually add backslashes so you don't have to, it doesn't "magically" retain the backslashes, instead it replaces them with double backslashes so they are interpreted as single backslashes.
Look at the following example:
>>> s = r"\rando\\\mst\ri\ngo\\flet\ters"
>>> s
'\\rando\\\\\\mst\\ri\\ngo\\\\flet\\ters'
>>> print(s)
\rando\\\mst\ri\ngo\\flet\ters
>>>
The string actually contains double backslashes and when printed they are interpreted as single backslashes.
I have a dataset containing some some poorly parsed text that includes a lot of unicode characters (like 'a', '{', 'Ⅷ', '♞', ...) that have been improperly converted to Unicode.
All of the backslashes are escaped, so every unicode escape sequence was interpreted as a \ next to a u instead of a single character, \u.
More specifically, I have strings that look like this:
>>> '\\u00e9'
'\\u00e9'
And I want them to look like this:
>>> '\u00e9'
'é'
How can I convert the first string to the second?
Here is one way to accomplish without importing another module.
input_string = '\\u00e9'
print(input_string.encode('latin-1').decode('unicode-escape'))
# output
é
First you need to identify the string as hex
classmethod fromhex(string)
This bytes class method returns a bytes object, decoding the given string object. The string must contain two hexadecimal digits per byte, with ASCII whitespace being ignored.
https://docs.python.org/3/library/stdtypes.html#bytes.fromhex
Next we need to convert the hex to Unicode
bytes.decode(encoding="utf-8", errors="strict")
https://docs.python.org/3/library/stdtypes.html#bytes.decode
So it would look something like this
char = '\\u00e9'
print (bytes.fromhex(char)[3:-1].decode('latin-1'))
I have a list like this
dis=('a','b','c',100)
I want it to push to a .Csv file(plan_to_prod2) ,but my folder name is a integer
my_df = pd.DataFrame(dis)
my_df.to_csv('E:\23\4\plan_to_prod2.csv')
i am getting invalid file name as error even though my file name is correct
You should use a raw string literal.
A \ followed by an integer is interpreted as a unicode character which is an invalid file name. Try print('E:\23\4\plan_to_prod2.csv') and see the output (I would have pasted it here but these characters don't show up when the answer is rendered). You can also see the problem in the error you provided in the comment.
When using raw string:
print(r'E:\23\4\plan_to_prod2.csv')
# E:\23\4\plan_to_prod2.csv
Instead of using raw string you can also use double slashes, ie print('E:\\23\\4\\plan_to_prod2.csv') but I find using raw strings much easier.
The \ character is used for escapes. So when you try to find the path you escape.
You should use / or use raw string r'' instead of \. Also, you could escape those backslashes by escaping it with an additional \.Choose whichever suits you best.
r'E:\23\4\plan_to_prod2.csv'
'E:\\23\\4\\plan_to_prod2.csv'
'E:/23/4/plan_to_prod2.csv'
While asking this question, I realized I didn't know much about raw strings. For somebody claiming to be a Django trainer, this sucks.
I know what an encoding is, and I know what u'' alone does since I get what is Unicode.
But what does r'' do exactly? What kind of string does it result in?
And above all, what the heck does ur'' do?
Finally, is there any reliable way to go back from a Unicode string to a simple raw string?
Ah, and by the way, if your system and your text editor charset are set to UTF-8, does u'' actually do anything?
There's not really any "raw string"; there are raw string literals, which are exactly the string literals marked by an 'r' before the opening quote.
A "raw string literal" is a slightly different syntax for a string literal, in which a backslash, \, is taken as meaning "just a backslash" (except when it comes right before a quote that would otherwise terminate the literal) -- no "escape sequences" to represent newlines, tabs, backspaces, form-feeds, and so on. In normal string literals, each backslash must be doubled up to avoid being taken as the start of an escape sequence.
This syntax variant exists mostly because the syntax of regular expression patterns is heavy with backslashes (but never at the end, so the "except" clause above doesn't matter) and it looks a bit better when you avoid doubling up each of them -- that's all. It also gained some popularity to express native Windows file paths (with backslashes instead of regular slashes like on other platforms), but that's very rarely needed (since normal slashes mostly work fine on Windows too) and imperfect (due to the "except" clause above).
r'...' is a byte string (in Python 2.*), ur'...' is a Unicode string (again, in Python 2.*), and any of the other three kinds of quoting also produces exactly the same types of strings (so for example r'...', r'''...''', r"...", r"""...""" are all byte strings, and so on).
Not sure what you mean by "going back" - there is no intrinsically back and forward directions, because there's no raw string type, it's just an alternative syntax to express perfectly normal string objects, byte or unicode as they may be.
And yes, in Python 2.*, u'...' is of course always distinct from just '...' -- the former is a unicode string, the latter is a byte string. What encoding the literal might be expressed in is a completely orthogonal issue.
E.g., consider (Python 2.6):
>>> sys.getsizeof('ciao')
28
>>> sys.getsizeof(u'ciao')
34
The Unicode object of course takes more memory space (very small difference for a very short string, obviously ;-).
There are two types of string in Python 2: the traditional str type and the newer unicode type. If you type a string literal without the u in front you get the old str type which stores 8-bit characters, and with the u in front you get the newer unicode type that can store any Unicode character.
The r doesn't change the type at all, it just changes how the string literal is interpreted. Without the r, backslashes are treated as escape characters. With the r, backslashes are treated as literal. Either way, the type is the same.
ur is of course a Unicode string where backslashes are literal backslashes, not part of escape codes.
You can try to convert a Unicode string to an old string using the str() function, but if there are any unicode characters that cannot be represented in the old string, you will get an exception. You could replace them with question marks first if you wish, but of course this would cause those characters to be unreadable. It is not recommended to use the str type if you want to correctly handle unicode characters.
'raw string' means it is stored as it appears. For example, '\' is just a backslash instead of an escaping.
Let me explain it simply:
In python 2, you can store string in 2 different types.
The first one is ASCII which is str type in python, it uses 1 byte of memory. (256 characters, will store mostly English alphabets and simple symbols)
The 2nd type is UNICODE which is unicode type in python. Unicode stores all types of languages.
By default, python will prefer str type but if you want to store string in unicode type you can put u in front of the text like u'text' or you can do this by calling unicode('text')
So u is just a short way to call a function to cast str to unicode. That's it!
Now the r part, you put it in front of the text to tell the computer that the text is raw text, backslash should not be an escaping character. r'\n' will not create a new line character. It's just plain text containing 2 characters.
If you want to convert str to unicode and also put raw text in there, use ur because ru will raise an error.
NOW, the important part:
You cannot store one backslash by using r, it's the only exception.
So this code will produce error: r'\'
To store a backslash (only one) you need to use '\\'
If you want to store more than 1 characters you can still use r like r'\\' will produce 2 backslashes as you expected.
I don't know the reason why r doesn't work with one backslash storage but the reason isn't described by anyone yet. I hope that it is a bug.
A "u" prefix denotes the value has type unicode rather than str.
Raw string literals, with an "r" prefix, escape any escape sequences within them, so len(r"\n") is 2. Because they escape escape sequences, you cannot end a string literal with a single backslash: that's not a valid escape sequence (e.g. r"\").
"Raw" is not part of the type, it's merely one way to represent the value. For example, "\\n" and r"\n" are identical values, just like 32, 0x20, and 0b100000 are identical.
You can have unicode raw string literals:
>>> u = ur"\n"
>>> print type(u), len(u)
<type 'unicode'> 2
The source file encoding just determines how to interpret the source file, it doesn't affect expressions or types otherwise. However, it's recommended to avoid code where an encoding other than ASCII would change the meaning:
Files using ASCII (or UTF-8, for Python 3.0) should not have a coding cookie. Latin-1 (or UTF-8) should only be used when a comment or docstring needs to mention an author name that requires Latin-1; otherwise, using \x, \u or \U escapes is the preferred way to include non-ASCII data in string literals.
Unicode string literals
Unicode string literals (string literals prefixed by u) are no longer used in Python 3. They are still valid but just for compatibility purposes with Python 2.
Raw string literals
If you want to create a string literal consisting of only easily typable characters like english letters or numbers, you can simply type them: 'hello world'. But if you want to include also some more exotic characters, you'll have to use some workaround.
One of the workarounds are Escape sequences. This way you can for example represent a new line in your string simply by adding two easily typable characters \n to your string literal. So when you print the 'hello\nworld' string, the words will be printed on separate lines. That's very handy!
On the other hand, sometimes you might want to include the actual characters \ and n into your string – you might not want them to be interpreted as a new line. Look at these examples:
'New updates are ready in c:\windows\updates\new'
'In this lesson we will learn what the \n escape sequence does.'
In such situations you can just prefix the string literal with the r character like this: r'hello\nworld' and no escape sequences will be interpreted by Python. The string will be printed exactly as you created it.
Raw string literals are not completely "raw"?
Many people expect the raw string literals to be raw in a sense that "anything placed between the quotes is ignored by Python". That is not true. Python still recognizes all the escape sequences, it just does not interpret them - it leaves them unchanged instead. It means that raw string literals still have to be valid string literals.
From the lexical definition of a string literal:
string ::= "'" stringitem* "'"
stringitem ::= stringchar | escapeseq
stringchar ::= <any source character except "\" or newline or the quote>
escapeseq ::= "\" <any source character>
It is clear that string literals (raw or not) containing a bare quote character: 'hello'world' or ending with a backslash: 'hello world\' are not valid.
Maybe this is obvious, maybe not, but you can make the string '\' by calling x=chr(92)
x=chr(92)
print type(x), len(x) # <type 'str'> 1
y='\\'
print type(y), len(y) # <type 'str'> 1
x==y # True
x is y # False