Python u string prefix
Not sure with unicode, but generally you can call str. For instance, subprocess output captured in Python 3. You could use Python 3.
The default string type is unicode, so the u'' prefix is no longer required. The u comes from the unicode. If you use the unicode builtin to construct all your strings, you could do something like.
It's like a mouse trying to eat an elephant. If you treat Unicode as providing an abstract space for any character you need, ASCII is accommodated in that without any need to treat it as a special case. You could override sys.
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Suppress the u'prefix indicating unicode' in python strings 8 Is there a way to globally suppress the unicode string indicator in python? For just a string, wrapping thyroid nose swelling str seems to work for me. In short, no. You cannot turn this off.
Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Which is not what I was expecting extensions. Obviously stupid mebecause I have used lstrip wrongly: lstrip will remove all characters which appear in the passed chars string, not considering that string as a real string, but as "a set of characters to remove from the beginning of the string".
I think you can use methods of the str type to do this. There's no need for regular expressions:. As an aside note, str is a bad name for a variable because it shadows the str type. Learn more. Remove a prefix from a string [duplicate] Ask Question. Asked 6 years, 10 months ago. Active 1 year, 8 months ago. Viewed 77k times. Is there a standard way to remove a substring from the beginning of a string? Active Oldest Votes. I don't know about "standard way". Elazar Elazar And you can't decide you want it to raise an exception otherwise.
Too clever! But can you make it Raise something in the error case, and still fit it in 2 lines x 80 columns? Blckknght Blckknght 75k 9 9 gold badges 84 84 silver badges bronze badges. Haidro: Whoops, that's what I intended to do, I just didn't type it correctly. I suppose you could also return the result of the replace call. Zacrath Zacrath 2 2 silver badges 8 8 bronze badges. The Overflow Blog. Podcast Programming tutorials can be a real drag. Featured on Meta. Community and Moderator guidelines for escalating issues via new response….
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In a python source code I stumbled upon I've seen a small b before a string like in:. I know about the u prefix signifying a unicode string, and the r prefix for a raw string literal.
What does the b stand for and in which kind of source code is it useful as it seems to be exactly like a plain string without any prefix? This is Python3 bytes literal. This prefix is absent in Python 2. In Python 2. The b prefix signifies a bytes string literal. If you see it used in Python 3 source code, the expression creates a bytes objectnot a regular Unicode str object. If you see it echoed in your Python shell or as part of a list, dict or other container contents, then you see a bytes object represented using this notation.
Because a bytes object consist of a sequence of integers, you can construct a bytes object from any other sequence of integers with values in the range, like a list:.
Python - Strings
If your bytes value does contain text, you need to first decode it, using the correct codec. If the data is encoded as UTF-8, for example, you can obtain a Unicode str value with:.
Conversely, to go from text in a str object to bytes you need to encode. You need to decide on an encoding to use; the default is to use UTF-8, but what you will need is highly dependent on your use case:.
Both the decoding and encoding methods take an extra argument to specify how errors should be handled. Python 2, versions 2. Use a bytearray object if you need to have a mutable bytes value. Learn more. What does a b prefix before a python string mean? Ask Question. Asked 10 years ago. Active 5 months ago.
Viewed 49k times. In a python source code I stumbled upon I've seen a small b before a string like in: b"abcdef" I know about the u prefix signifying a unicode string, and the r prefix for a raw string literal. SLott: follow the link you provided you'll see the b prefix is not allowed in string prefix And googling about these kind of things is not easy.
I tried keywords like "b python string prefix" and got basically nowhere.Strings are amongst the most popular types in Python. We can create them simply by enclosing characters in quotes. Python treats single quotes the same as double quotes. Creating strings is as simple as assigning a value to a variable.Postfix to Infix Conversion - Examples - Data Structures - Lec-17 - Bhanu Priya
Python does not support a character type; these are treated as strings of length one, thus also considered a substring.
To access substrings, use the square brackets for slicing along with the index or indices to obtain your substring. You can "update" an existing string by re assigning a variable to another string. The new value can be related to its previous value or to a completely different string altogether.
Python String startswith() Method
Following table is a list of escape or non-printable characters that can be represented with backslash notation. This operator is unique to strings and makes up for the pack of having functions from C's printf family.
When the above code is executed, it produces the following result. Note how every single special character has been converted to its printed form, right down to the last NEWLINE at the end of the string between the "up. Raw strings do not treat the backslash as a special character at all. Now let's make use of raw string. This allows for a more varied set of characters, including special characters from most languages in the world.
Counts how many times str occurs in string or in a substring of string if starting index beg and ending index end are given. Decodes the string using the codec registered for encoding.
Returns encoded string version of string; on error, default is to raise a ValueError unless errors is given with 'ignore' or 'replace'. Determines if string or a substring of string if starting index beg and ending index end are given ends with suffix; returns true if so and false otherwise. Determine if str occurs in string or in a substring of string if starting index beg and ending index end are given returns index if found and -1 otherwise.
Returns true if string has at least 1 character and all characters are alphanumeric and false otherwise. Returns true if string has at least 1 character and all characters are alphabetic and false otherwise.
Returns true if string has at least 1 cased character and all cased characters are in lowercase and false otherwise. Returns true if string has at least one cased character and all cased characters are in uppercase and false otherwise.
Merges concatenates the string representations of elements in sequence seq into a string, with separator string. Returns a space-padded string with the original string left-justified to a total of width columns. Returns a space-padded string with the original string right-justified to a total of width columns.
Splits string according to delimiter str space if not provided and returns list of substrings; split into at most num substrings if given. Determines if string or a substring of string if starting index beg and ending index end are given starts with substring str; returns true if so and false otherwise.
Returns "titlecased" version of string, that is, all words begin with uppercase and the rest are lowercase. Translates string according to translation table str charsremoving those in the del string. Returns original string leftpadded with zeros to a total of width characters; intended for numbers, zfill retains any sign given less one zero. Python - Strings Advertisements. Previous Page.A Python program is read by a parser.
Input to the parser is a stream of tokensgenerated by the lexical analyzer. This chapter describes how the lexical analyzer breaks a file into tokens. New in version 2. For compatibility with older versions, Python only warns if it finds 8-bit characters; those warnings should be corrected by either declaring an explicit encoding, or using escape sequences if those bytes are binary data, instead of characters.
Future compatibility note: It may be tempting to assume that the character set for 8-bit characters is ISO Latin-1 an ASCII superset that covers most western languages that use the Latin alphabetbut it is possible that in the future Unicode text editors will become common.
While there is no consensus on this subject yet, it is unwise to assume either Latin-1 or UTF-8, even though the current implementation appears to favor Latin This applies both to the source character set and the run-time character set. A logical line is constructed from one or more physical lines by following the explicit or implicit line joining rules. A physical line is a sequence of characters terminated by an end-of-line sequence.
All of these forms can be used equally, regardless of platform. The end of input also serves as an implicit terminator for the final physical line. A comment starts with a hash character that is not part of a string literal, and ends at the end of the physical line.
A comment signifies the end of the logical line unless the implicit line joining rules are invoked. Comments are ignored by the syntax; they are not tokens. The encoding declaration must appear on a line of its own.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. You're right, see 3. Unicode Strings. Python 3 made them redundant, as the default string type is Unicode.
Versions 3. Q: I'm in a terrible, awful hurry and I landed here from Google Search. I'm trying to write this data to a file, I'm getting an error, and I need the dead simplest, probably flawed, solution this second. A: Fine. But you should really read some of the answers and discussion on Converting a Unicode string and this excellent, excellent, primer on character encoding.
In Python 3. Note: in Python 3. I came here because I had funny-char-syndrome on my requests output. I thought response. Turns out response. My solution was to get the raw bytes with 'response. I found that the following mindset helps a lot when dealing with Python strings: All Python manifest strings should use the u"" syntax.
The "" syntax is for byte arrays, only. Before the bashing begins, let me explain. Most Python programs start out with using "" for strings. But then they need to support documentation off the Internet, so they start using "". In this case, Unicode does act like a virus and will wreak havoc. But, if you follow my rule, you won't have this infection because you will already be infected.
Learn more. What's the u prefix in a Python string? Ask Question. Asked 10 years, 1 month ago. Active 9 months ago. Viewed k times. Like in: u'Hello' My guess is that it indicates "Unicode", is it correct? If so, since when is it available?Text Sequence Type — str. String Methods. This value is not locale-dependent. The lowercase letters 'abcdefghijklmnopqrstuvwxyz'. This value is not locale-dependent and will not change. The string ''. This includes the characters space, tab, linefeed, return, formfeed, and vertical tab.
The built-in string class provides the ability to do complex variable substitutions and value formatting via the format method described in PEP The Formatter class in the string module allows you to create and customize your own string formatting behaviors using the same implementation as the built-in format method. The Formatter class has the following public methods:.
The primary API method. It takes a format string and an arbitrary set of positional and keyword arguments. It is just a wrapper that calls vformat. Changed in version 3. This function does the actual work of formatting. It calls the various methods described below.
In addition, the Formatter defines a number of methods that are intended to be replaced by subclasses:. This is used by vformat to break the string into either literal text, or replacement fields. The values in the tuple conceptually represent a span of literal text followed by a single replacement field. Retrieve a given field value. The key argument will be either an integer or a string.
If it is an integer, it represents the index of the positional argument in args ; if it is a string, then it represents a named argument in kwargs. The args parameter is set to the list of positional arguments to vformatand the kwargs parameter is set to the dictionary of keyword arguments.
For compound field names, these functions are only called for the first component of the field name; subsequent components are handled through normal attribute and indexing operations. If the index or keyword refers to an item that does not exist, then an IndexError or KeyError should be raised. Implement checking for unused arguments if desired. The arguments to this function is the set of all argument keys that were actually referred to in the format string integers for positional arguments, and strings for named argumentsand a reference to the args and kwargs that was passed to vformat.
The set of unused args can be calculated from these parameters. The method is provided so that subclasses can override it.
The str. The syntax is related to that of formatted string literalsbut there are differences.