Python Strings
String is sequence of Unicode characters. We can use single quotes or double quotes to represent strings. Multi-line strings can be denoted using triple quotes, ”’ or “””.
>>> s = ‘This is a string’
>>> s = “This is a string”
>>> s = ”’a multiline
text ”’
>>> s=””” Hello this is multiline
text”””
Like list and tuple, slicing operator [ ] can be used with string. Strings are immutable(cannot be modified).
Example:1
s = 'Hello world!'
print(s)
print(s[0])
print(s[1])
print("s[4] = ", s[4])
print("s[6:11] = ", s[6:11])
# Generates error
# Strings are immutable in Python
#s[5] ='d'
Output:
Hello world! H e s[4] = o s[6:11] = world >>>
Python Dictionary
Dictionary is an unordered collection of key-value pairs. It is generally used when we have a huge amount of data. Dictionaries are optimized for retrieving data. We must know the key to retrieve the value.
In Python, dictionaries are defined within braces {} with each item being a pair in the form key:value. Key and value can be of any type.
>>> d = {1:’value’,’key’:2}
>>> type(d)
<class ‘dict’>
We use key to retrieve the respective value. But not the other way around.
example:1:
d = {1:'one',2:'two',3:'three',4:'four',5:'five'}
print(type(d))
print(d)
Output:
<class 'dict'>
{1: 'one', 2: 'two', 3: 'three', 4: 'four', 5: 'five'}
>>>
Example:2
d = {1:'one',2:'two',3:'three',4:'four',5:'five'}
print(type(d))
print(d)
print("d[1] = ", d[1]);
print("d[2] = ", d[2]);
print("d[3] = ", d[3]);
print("d[4] = ", d[4]);
print("d[5] = ", d[5]);
Output:
<class 'dict'>
{1: 'one', 2: 'two', 3: 'three', 4: 'four', 5: 'five'}
d[1] = one
d[2] = two
d[3] = three
d[4] = four
d[5] = five
>>>
