Python Articles - Page 782 of 829

The following code does the replacement in the given text file. After the replacement, the text is written to a new text file 'bar.txt'Examplef1 = open('foo.txt', 'r') f2 = open('bar.txt', 'w') for line in f1:     print line     f2.write(line.replace('Poetry', 'Prose')) f2 = open('bar.txt', 'r') for line in f2:    print line, f1.close() f2.close()OutputThis gives the outputPoetry is often considered the oldest form of literature. Poetry today is usually  written down, but is still sometimes performed. Prose is often considered the oldest form of literature. Prose today is usually written down, but is still sometimes performed.Read More

Concept of variable in Python is different from C/C++. In C/C++, variable is a named location in memory. Even if value of one is assigned to another, it creates a copy in another location.int x=5; int y=x;For example in C++, the & operator returns address of the declared variable.cout

A string contains two integers separated by comma. It is first split in a list of two strings having digits.>>> s="1,2".split(",") >>> s ['1', '2']Two items are then converted to integers and used as arguments for complex() function>>> complex(int(s[0]), int(s[1])) (1+2j)This results in unpacking of string of integers in a complex number

List is an ordered sequence of elements. Individual element in list is accessed using index starting with 0 and goes up to length-1. If index goes beyond this range, IndexError exception is encountered.In following example, an infinite loop is used to pop one element at a time. As loop tries to go even after last element is popped, IndexError exception will be encountered. We trap it using try – except mechanism.a=[1,2,3] while True:   try:     b=a.pop()     print (b)   except (IndexError):     break

We can compare given strings using the following codeExampleimport re s1 = 'Pink Forest' s2 = 'Pink Forrest' if bool(re.search(s1,s2))==True:    print 'Strings match' else:    print 'Strings do not match'OutputThis gives the outputStrings do not match

In this article, we will explain nested/inner functions in Python and how they work with examples. Nested (or inner) functions are functions defined within other functions that allow us to directly access the variables and names defined in the enclosing function. Nested functions can be used to create closures and decorators, among other things. Defining an inner/nested Function Simply use the def keyword to initialize another function within a function to define a nested function. The following program is to demonstrate the inner function in Python − Example # creating an outer function def outerFunc(sample_text): sample_text ... Read More

The function datetime.now() takes tzinfo as keyword argument but datetime.today() does not take any keyword arguments. Quoting the docs −datetime.now() returns the current local date and time. If optional argument tz is None or not specified, this is like today(), but, if possible, supplies more precision than can be gotten from going through a time.time() timestamp (for example, this may be possible on platforms supplying the C gettimeofday() function).

In this article, we will show you how to convert date and time with different timezones in Python. Using astimezone() function Using datetime.now() function The easiest way in Python date and time to handle timezones is to use the pytz module. This library allows accurate and cross−platform timezone calculations. pytz brings the Olson tz database into Python. It also solves the issue of ambiguous times at the end of daylight saving time, which you can read more about in the Python Library Reference (datetime.tzinfo) Before you use it you'll need to install it using − pip install pytz ... Read More

In this article, we will show you how to compare time to different timezones in Python using the below methods. Comparing the given Timezone with the local TimeZone Comparing the Current Datetime of Two Timezones Comparing Two Times with different Timezone Method 1: Comparing the given Timezone with the local TimeZone Algorithm (Steps) Following are the Algorithm/steps to be followed to perform the desired task – Use the import keyword, to import the datetime, pytz modules. Use the timezone() function (gets the time zone of a specific location) of the pytz module, to get the timezone ... Read More

In this article, we will show you how to do date validation in Python. Now we see 2 methods to accomplish this task− Using datetime.strptime() function Using dateutil.parser.parse() function Method 1: Using datetime.strptime() function Algorithm (Steps) Following are the Algorithm/steps to be followed to perform the desired task − Use the import keyword, to import the datetime (To work with dates and times) module. Enter the date as a string and create a variable to store it. Enter the date format as a string and create another variable to store it. Use the try−except blocks for handling the ... Read More