## What is a Python bytestring?

Updated on 30-Sep-2019 08:21:31
A string is a sequence of characters; these are an abstract concept, and can't be directly stored on disk. A byte string is a sequence of bytes - things that can be stored on disk. The mapping between them is an encoding - there are quite a lot of these (and infinitely many are possible) - and you need to know which applies in the particular case in order to do the conversion, since a different encoding may map the same bytes to a different string. For example, the same byte string can represent 2 different strings in 2 different ... Read More

## How do I wrap a string in a file in Python?

Updated on 30-Sep-2019 08:22:16
To create a file-like object (same duck type as File) with the contents of a string, you can use the StringIO module. Pass your string to the constructor of StringIO and then you can use it as a file like object. For example,>>> from cStringIO import StringIO >>> f = StringIO('Hello world') >>> f.read() 'Hello world'In Python 3, use the io module. For example,>>> import io >>> f = io.StringIO('Hello world') >>> f.read() 'Hello world'Note that StringIO doesn't accept Unicode strings that cannot be encoded as plain ASCII strings.

## How to replace \\ with in Python?

Updated on 30-Sep-2019 08:23:04
There are two ways to go about replacing \ with \ or unescaping backslash escaped strings in Python. First is using literal_eval to evaluate the string. Note that in this method you need to surround the string in another layer of quotes. For example:>>> import ast >>> a = '"Hello,world"' >>> print ast.literal_eval(a) Hello, worldAnother way is to use the decode('string_escape') method from the string class. For example,>>> print "Hello,world".decode('string_escape') Hello, world

## How to correctly sort a string with a number inside in Python?

Updated on 30-Sep-2019 08:24:05
This type of sort in which you want to sort on the basis of numbers within string is called natural sort or human sort. For example, if you have the text:['Hello1', 'Hello12', 'Hello29', 'Hello2', 'Hello17', 'Hello25'] Then you want the sorted list to be:['Hello1', 'Hello2', 'Hello12', 'Hello17', 'Hello25', 'Hello29'] and not:['Hello1', 'Hello12', 'Hello17', 'Hello2', 'Hello25', 'Hello29'] To do this we can use the extra parameter that sort() uses. This is a function that is called to calculate the key from the entry in the list. We use regex to extract the number from the string and sort on both text and number.  import re ... Read More

## How to replace the last occurrence of an expression in a string in Python?

Updated on 30-Sep-2019 08:25:24
This problem can be solved by reversing the string, reversing the string to be replaced, replacing the string with reverse of string to be replaced with and finally reversing the string to get the result. You can reverse strings by simple slicing notation - [::-1]. To replace the string you can use str.replace(old, new, count). For example,  def rreplace(s, old, new):     return (s[::-1].replace(old[::-1], new[::-1], 1))[::-1]  rreplace('Helloworld, hello world, hello world', 'hello', 'hi') This will give the output:'Hello world, hello world, hi world'Another method by which you can do this is to reverse split the string once on the old string ... Read More

## How can I test if a string starts with a capital letter using Python?

Updated on 26-Oct-2022 08:12:36
A string is a collection of characters that can represent a single word or a whole sentence. Unlike Java there is no need to declare Python strings explicitly we can directly assign string value to a literal. A string in Python is represented by a string class which provides several functions and methods using which you can perform various operations on strings. In this article, we are going to find out how to test if a string starts with a capital letter using Python. Using isupper() method One way to achieve this is using the inbuilt string method isupper(). We ... Read More

## How to convert a string to dictionary in Python?

Updated on 30-Sep-2019 08:27:13
We can use ast.literal_eval() here to evaluate the string as a python expression. It safely evaluates an expression node or a string containing a Python expression.The string or node provided may only consist of the following Python literal structures: strings, numbers, tuples, lists, dicts, booleans, and None. For example:  >>>import ast >>>x = ast.literal_eval("{'foo' : 'bar', 'hello' : 'world'}") >>>type(x)  Dictionaries can also be seen as JSON strings. Thus we can use the json module to convert a string to dict as well. For example,  >>>import json >>>x = json.loads("{'foo' : 'bar', 'hello' : 'world'}") >>>type(x) Read More

## How to check whether a string starts with XYZ in Python?

Updated on 26-Oct-2022 07:59:07
A string is a collection of characters stored as a single value. Un like other technologies there is no need to explicitly declare strings in python (for that matter any variable), you just need to assign strings to a literal this makes Python strings easy to use. In Python, a string is represented by the class named String. This class provides several functions and methods using which you can perform various operations on strings. In this article, we are going to find out how to check whether a string starts with XYZ in Python. Using startswith() method One way to ... Read More

## How to wrap long lines in Python?

Updated on 26-Oct-2022 07:52:45
A string is a collection of characters that can represent a single word or a whole sentence. Unlike Java there is no need to declare Python strings explicitly we can directly assign string value to a literal. A string in Python is represented by a string class which provides several functions and methods using which you can perform various operations on strings. In this article, we are going to find out how to wrap long lines in Python. Using parenthesized line breaks One way to achieve this is by using parenthesized line breaks. Using Python's inferred line continuation within parentheses, ... Read More

## How do I check if raw input is integer in Python 3?

Updated on 30-Sep-2019 08:29:53
There is a method called isdigit() in String class that returns true if all characters in the string are digits and there is at least one character, false otherwise. Even if you input a float, it'll return false. You can call it as follows:>>> x = raw_input() 12345 >>> x.isdigit() TrueYou can also use regexes for the same result. For matching only digits, we can call the re.match(regex, string) using the regex: "^[0-9]+$". For example, >>> x = raw_input() 123abc >>> bool(re.match('^[0-9]+$', x)) Falsere.match returns an object, to check if it exists or not, we need to convert it to ... Read More