a. int in Pythin<\/strong><\/p>\nint stands for integer. The integer data type in Python holds signed integers. We can use the type() function to find which class it belongs to.<\/p>\n
>>> a=-7\r\n>>> type(a)<\/pre>\nOutput<\/strong><\/p>\n<class ‘int’><\/strong><\/div>\nAn integer can be of any length, with the only limitation being the available memory.<\/p>\n
>>> a=9999999999999999999999999999999\r\n>>> type(a)<\/pre>\nOutput<\/strong><\/p>\n<class ‘int’><\/strong><\/div>\nb. float in Python<\/strong><\/p>\nThe float data type in Python holds floating-point real values. An int can only store the number 3, but a float can store 3.25 if you want.<\/p>\n
>>> a=3.0\r\n>>> type(a)<\/pre>\nOutput<\/strong><\/p>\n<class ‘float’><\/strong><\/div>\nc. long<\/strong><\/p>\nLong Data type in Python holds a long integer of unlimited length. But this construct does not exist in Python 3.x.<\/p>\n
d. complex<\/strong><\/p>\nA complex data type in Python holds a complex number. A complex number looks like this: a+bj Here, a and b are the real parts of the number, and j is imaginary.<\/p>\n
>>> a=2+3j\r\n>>> type(a)<\/pre>\nOutput<\/strong><\/p>\n<class ‘complex’><\/strong><\/div>\nUse the isinstance() function to tell if Python variables belong to a particular class. It takes two parameters- the variable\/value, and the class.<\/p>\n
>>> print(isinstance(a,complex))<\/pre>\nOutput<\/strong><\/p>\nTrue<\/strong><\/div>\n2. Python Strings<\/h4>\n
A string is a sequence of characters. Python does not have a char data type, unlike C++ or Java. You can delimit a string using single quotes or double quotes.<\/p>\n
>>> city='Ahmedabad'\r\n>>> city<\/pre>\nOutput<\/strong><\/p>\n‘Ahmedabad’<\/strong><\/div>\n>>> city=\"Ahmedabad\"\r\n>>> city<\/pre>\nOutput<\/strong><\/p>\n‘Ahmedabad’<\/strong><\/div>\na. Spanning a String Across Lines in Python<\/span><\/strong><\/p>\nTo span a string across multiple lines, you can use triple quotes.<\/p>\n
>>> var=\"\"\"If\r\nonly\"\"\"\r\n>>> var<\/pre>\nOutput<\/strong><\/p>\n‘If\\n\\tonly’<\/strong><\/div>\n>>> print(var)<\/pre>\nOutput<\/strong><\/p>\nIf<\/strong>
\nOnly<\/strong><\/div>\n>>> \"\"\"If\r\nonly\"\"\"<\/pre>\nOutput<\/strong><\/p>\n‘If\\n\\tonly’<\/strong><\/div>\nAs you can see, the quotes preserved the formatting (\\n is the escape sequence for newline, \\t is for tab).<\/p>\n
b. Displaying Part of a String in Python<\/strong><\/p>\nYou can display a character from a string using its index in the string. Remember, indexing starts with 0.<\/p>\n
>>> lesson='disappointment'\r\n>>> lesson[0]<\/pre>\nOutput<\/strong><\/p>\n‘d’<\/strong><\/div>\nYou can also display a burst of characters in a string using the slicing operator [].<\/p>\n
>>> lesson[5:10]<\/pre>\nOutput<\/strong><\/p>\n‘point’<\/strong><\/div>\nThis prints the characters from 5 to 9.<\/p>\n
c. String Formatters in Python<\/strong><\/p>\nString formatters in Python allow us to print characters and values at once. You can use the % operator.<\/p>\n
>>> x=10;\r\n>>>\u00a0printer=\"Dell\"\r\n>>> print(\"I just printed %s pages to the printer %s\" % (x, printer))\r\n\r\n<\/pre>\nOr you can use the format method.<\/p>\n
>>> print(\"I just printed {0} pages to the printer {1}\".format(x, printer))\r\n>>> print(\"I\u00a0 just printed {x} pages to the printer {printer}\".format(x=7, printer=\"Dell\"))<\/pre>\nA third option is to use f-strings.<\/p>\n
>>> print(f\"I just printed {x} pages to the printer {printer}\")<\/pre>\nd. String Concatenation in Python<\/strong><\/p>\nYou can concatenate(join) strings in Python.<\/p>\n
>>> a='10'\r\n>>> print(a+a)<\/pre>\nOutput<\/strong><\/p>\n1010<\/strong><\/div>\nHowever, you cannot concatenate values of different types.<\/p>\n
>>> print('10'+10)<\/pre>\nOutput<\/strong><\/p>\n\n
Traceback (most recent call last):<\/strong>File “<pyshell#89>”, line 1, in <module>;<\/strong><\/p>\nprint(’10’+10)<\/strong><\/p>\nTypeError: must be str, not int<\/strong><\/p>\n<\/div>\n3. Python Lists<\/h4>\n
A list is a collection of values. Remember, it may contain different types of values.<\/p>\n
To define a list in Python, you must put values separated by commas in square brackets. You don\u2019t need to declare a type for a list either.<\/p>\n
>>> days=['Monday','Tuesday',3,4,5,6,7]\r\n>>> days<\/pre>\nOutput<\/strong><\/p>\n[‘Monday’, ‘Tuesday’, 3, 4, 5, 6, 7]<\/strong><\/div>\na. Slicing a List in Python<\/strong><\/p>\nYou can slice a list in python the way you\u2019d slice a string- with the slicing operator.<\/p>\n
>>> days[1:3]<\/pre>\nOutput<\/strong><\/p>\n[‘Tuesday’, 3]<\/strong><\/div>\nIndexing for a list begins with 0, like for a string. Python doesn\u2019t have arrays.<\/p>\n
b. Finding the Length of a List in Python<\/strong><\/p>\nPython supports an inbuilt function to calculate the length of a list.<\/p>\n
>>> len(days)<\/pre>\nOutput<\/strong><\/p>\n7<\/strong><\/div>\nc. Reassigning Elements of a List<\/strong><\/p>\nA list is mutable in Python. This means that you can reassign elements later on.<\/p>\n
>>> days[2]='Wednesday'\r\n>>> days<\/pre>\nOutput<\/strong><\/p>\n[‘Monday’, ‘Tuesday’, ‘Wednesday’, 4, 5, 6, 7]<\/strong><\/div>\nd. Iterating on the List in Python<\/strong><\/p>\nTo iterate over the list in Python, we can use the for loop. By iterating, we can access each element one by one, which is very helpful when we need to perform some operations on each element of a list.<\/p>\n
nums = [1,2,5,6,8]\r\nfor n in nums:\r\n print(n)\r\n<\/pre>\nOutput<\/strong><\/p>\n1
\n2
\n5
\n6
\n8<\/div>\n
e. Multidimensional Lists<\/strong><\/p>\nA list may have more than one dimension. Have a detailed look at this in DataFlair’s tutorial on Python Lists<\/strong><\/em><\/a>.<\/p>\n>>> a=[[1,2,3],[4,5,6]]\r\n>>> a<\/pre>\nOutput<\/strong><\/p>\n[[1, 2, 3], [4, 5, 6]]<\/strong><\/div>\n4. Python Tuples<\/h4>\n
A tuple in Python is like a list. You declare it using parentheses instead.<\/p>\n
>>> subjects=('Physics','Chemistry','Maths')\r\n>>> subjects<\/pre>\nOutput<\/strong><\/p>\n(‘Physics’, ‘Chemistry’, ‘Maths’)<\/strong><\/div>\na. Accessing and Slicing a Tuple in Python<\/strong><\/p>\nYou access a tuple in Python the same way as you\u2019d access a list. The same goes for slicing it.<\/p>\n
>>> subjects[1]<\/pre>\nOutput<\/strong><\/p>\n‘Chemistry’<\/strong><\/div>\n>>> subjects[0:2]<\/pre>\n
![\"variables](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2019\/12\/python-variables-2-1.jpg\")
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