Table of contents
Length of a String:
We can find length of a string using len() function.
Example 01:
names = "Python, Java"
print(len(names)) #output = 12
Example 02:
fruit = "Mango"
len1 = len(fruit)
print("Mango is a", len1, "letter word.")
#output: Mango is a 5 letter word.
String as an array:
A string is essentially a sequence of characters also called an array. Thus we can access the elements of this array.
Example 01:
pie = "ApplePie"
print(pie[:5]) #output= Apple
print(pie[6]) #output = i (means returns character at specified index)
Example 02:
names = "Python, Javascript"
print(names[0:5]) #output = Python
Slicing of String:
It is used to return a particular range value. Slicing can be: Positive or Negative.
Syntax:
variable = [start : end : step]
start = From where, slicing starts. This number will be included.
end = From where, slicing starts. This number will be excluded, means "end-1"
step: It is the gap between the words/numbers.
\=> If step = 1 (positive value - means left to right) -> it is by-default
\=> step = -1 (negative value - means right to left)
Note:
For slicing we use square bracket.
Step is optional, we can write start and end only e.g. [start : end]
Slicing is same for string, list, tuple or dictionary etc.
Example 01:
Length of String:
fruit = "Mango" #string
mangoLen = len(fruit)
print(mangoLen) #output= 5
How it works:
For Length: M a n g o
# 1 2 3 4 5
For Slicing: Positive Indexing: M a n g o
# 0 1 2 3 4
For Slicing: Negative Indexing: M a n g o
# -5 -4 -3 -2 -1
Example 02: Positive Slicing:
fruit = "Mango"
#including 0 but not 4
print(fruit[0:4]) #Output = Mang
#at start python automatically assumes 0 =>including 0 but not 4 =[0:4]
print(fruit[:4]) #output = Mang
#including 1 but not 4
print(fruit[1:4]) #output = Man
#at start python automatically assumes 0
#at end it automatically assumes len of string.
print(fruit[:]) #Output = Mango
Example 03 - Negative String:
fruit = "Mango"
mangoLen = len(fruit) #output = 5
# Negative slicing
print(fruit[0:-3]) #output = Ma
Note: Negative slicing works as: if we have print(fruit[0:-3]) means total len = -3. Here total len is 5, so 5-3 = 2. So the answer will be print(fruit[0:2]) i.e. 'Ma' #including 0 but not 2
Example 04 - Negative String:
fruit = "Mango"
print(fruit[-1:-3]) #output = error (because 5-1=4 and 5-3=2
#so it will be [4:2] that doesnot possible)
Note: Here python didn't interpret anything, because total len = 5 so for print(fruit[-1:-3]), 5-1 = 4 and 5-3 = 2 then it become 'print(fruit[4:2])' - that doesn't make any sense
Example 05: When Step is also included
String = 'ASTRING'
# A S T R I N G
#positive index 0 1 2 3 4 5 6
#negative index -7 -6 -5 -4 -3 -2 -1
s1 = slice(3) #include 0 end before 3
s2 = slice(1, 5, 2) #include 1 end before 5 (gap of 2 words)
print("String slicing")
print(String[s1]) #output = AST
print(String[s2]) #output = SR
Output:
String slicing
AST
SR
Example 06:
String = 'GEEKSFORGEEKS'
# Example 1: Slicing from index 0 to 2 (stops at 3-1=2)
print(String[:3]) # Output: GEE
# Example 2: Slicing from index 1 to 5 (stops at 3-1=2), with a step of 2
print(String[1:5:2]) # Output: EK
# Example 3: Slicing from index -1 to -12 (stops at 3-1=2),
# with a step of -2
print(String[-1:-12:-2]) # Output: SKG
<< Previously ---------------------------------------------------- Next Lesson >>