PYTHON PROGRAMMING (2010)
Variable type
There are five main Data types which are as follows.
· Numbers
· String
· List
· Tuple
· Dictionary
Numbers
It contains numeric values and is created when value is assigned to them.
Example
var1 = 1
var2 = 10
Syntax of delete statement is as follows.
del var1[,var2[,var3[....,varN]]]]
Syntax for deleting multiple or single objects are as follows.
del var
del var_a, var_b
It supports four different numerical styles which are as follows.
· Int
· Long
· Float
· Complex
Strings
· It is identified as the set of characters.
· The plus sign is represented as the string concatenation operator.
· Similarly the asterisk is represented as the repetition operator.
Example
#!/usr/bin/python
str = 'Hello World!'
print str # Prints complete string
print str[0] # Prints first character of the string
print str[2:5] # Prints characters starting from 3rd to 5th
print str[2:] # Prints string starting from 3rd character
print str * 2 # Prints string two times
print str + "TEST" # Prints concatenated string.
Output
Hello World!
H
llo
llo World!
Hello World!Hello World!
Hello World!TEST.
List
These are written in between the brackets and with commas.
Example
#!/usr/bin/python
list = [ 'abcd', 786 , 2.23, 'john', 70.2 ]
tinylist = [123, 'john']
print list # Prints complete list
print list[0] # Prints first element of the list
print list[1:3] # Prints elements starting from 2nd till 3rd
print list[2:] # Prints elements starting from 3rd element
print tinylist * 2 # Prints list two times
print list + tinylist # Prints concatenated lists
Output
['abcd', 786, 2.23, 'john', 70.200000000000003]
abcd
[786, 2.23]
[2.23, 'john', 70.200000000000003]
[123, 'john', 123, 'john']
['abcd', 786, 2.23, 'john', 70.200000000000003, 123, 'john']
Tuples
It is also a similar sequenced data type like list.
Example
#!/usr/bin/python
tuple = ( 'abcd', 786 , 2.23, 'john', 70.2 )
tinytuple = (123, 'john')
print tuple # Prints complete list
print tuple[0] # Prints first element of the list
print tuple[1:3] # Prints elements starting from 2nd till 3rd
print tuple[2:] # Prints elements starting from 3rd element
print tinytuple * 2 # Prints list two times
print tuple + tinytuple # Prints concatenated lists
Output
('abcd', 786, 2.23, 'john', 70.200000000000003)
Abcd
(786, 2.23)
(2.23, 'john', 70.200000000000003)
(123, 'john', 123, 'john')
('abcd', 786, 2.23, 'john', 70.200000000000003, 123, 'john'
Dictionary
It is a kind of hash table and the values are enclosed in the curly bracket.
Example
#!/usr/bin/python
dict = {}
dict['one'] = "This is one"
dict[2] = "This is two"
tinydict = {'name': 'john','code':6734, 'dept': 'sales'}
print dict['one'] # Prints value for 'one' key
print dict[2] # Prints value for 2 key
print tinydict # Prints complete dictionary
print tinydict.keys() # Prints all the keys
print tinydict.values() # Prints all the values
Output
This is one
This is two
{'dept': 'sales', 'code': 6734, 'name': 'john'}
['dept', 'code', 'name']
['sales', 6734, 'john']
