Traversing A String With Python Programing

 

Traversing a String 

Iterating through the elements of a string, one character at a time is called traversing a given

string.

Concatenation of Strings 

‘+’ operator is used for concatenation of String. When used with numbers, ‘+’ performs addition

and is called the addition operators, but when used with Strings, it is called concatenation

operator since it joins or concatenates strings. 

s1="Core"  s2="Python"  s3=s1+s2  print(s3)  Out[ ]: CorePython

Numbers and Strings cannot be combined as operands with a ‘+’ or ‘-’ operator. 

s1+4  Traceback (most recent call last):  File "", line 1, in s1+4  TypeError: can only concatenate str (not "int") to str

Replication of Strings 

‘*’ operator when used with numbers performs multiplication but when used with a string and

a number performs replication of the string ‘number’ times. 

For replication, Python creates a new String that is a number of repetitions of the input String.

The original String is not modified as strings are immutable. New strings can be created but

existing strings cannot be modified. 

In[1]: "Python" * 2  Out[1]: 'PythonPython'  In[2]: "Python" * "Python"  Traceback (most recent call last):  File "", line 1, in "Python" * "Python"  TypeError: can't multiply sequence by non-int of type 'str' S

Indexing in Strings 

string	P	Y	T	H	O	N
+ve index	0	1	2	3	4	5
-ve index	-6	-5	-4	-3	-2	-1

The indexes of a string begin from 0 to (length-1) in forward direction (forward indexing)

and -1,-2,-3….,-length in the backward direction(backward indexing). 

Empty string: A string that has 0 characters. Just a pair of quotation marks.

In[1]: S=''         len(S)  Out[2]: 0

Length of a String 

Length of a string represents the number of characters(including spaces) in a String. len() function is used to find the length of the string. 

In[1]: s="Python"         len(s)  Out[2]: 6