Comments and String Operations
Comments in python​
A comments is a piece of code that ignored by the compiler and it is useful for human readers to understand the code better. Comments are useful for providing explanations, documenting code or temporarily.
1. Single Line Comment (#)
A single-line comment begins with a hash (#) symbol. The single-line comment is used to comment only one line of the code.
Example :
print("Hello World")
# This is Hello World program.
Output :
Hello World
Example Explanation :
In above example, you can created a single line comment by using the # character. You can also add comments at the end of a line of code like this # This is Hello World program.
2. Multiline Comment (""" """)
In Python Triple double quote (""") and single quote (''') are used for Multi-line commenting. Multi-line comment is useful when we need to comment on many lines.
Example :
print("Hello World!")
"""This is a Hello World program.
This is sample code.
We used multiple line commet"""
Example Explanation :
In above example, you can created a multi line comment starting with """ and ending with """.
String Manipulation​
1. upper()
upper() function is used to convert a string into uppercase.
Example :
myString = "road to code 4u"
print("Original String :",myString)
newString = myString.upper()
print("New String :",newString)
Output :
Original String : road to code 4u
New String : ROAD TO CODE 4U
Example Explanation :
In above example, we created 1st variable mystring for storing the string road to code 4u, then print the original string. upper() function is used to convert string into uppercase letter. We can created 2nd variable newString for store converted uppercase string. Output is ROAD TO CODE 4U.
2. lower()
lower() function is used to convert a string into lowercase.
Example :
myString = "ROAD TO CODE 4U"
print("Original String :",myString)
newString = myString.lower()
print("New String :",newString)
Output :
Original String : ROAD TO CODE 4U
New String : road to code 4u
Example Explanation :
In above example, we created 1st variable mystring for storing the string ROAD TO CODE 4U, then print the original string. lower() function is used to convert string into lowercase letter. We can created 2nd variable newString for store converted lowercase string. Output is road to code 4u.
3. strip()
strip() function removes white space (unnecessary spaces) from the end of the string.
Example :
str1 = "rtc4u"
str2 = "rtc4u "
print(str1)
print(str2.strip())
Output :
rtc4u
rtc4u
4. replace()
replace() function is used to replace the string.
Example :
myString = "roadtocode"
newString = myString.replace("o","#")
print(newString)
Output :
r#adt#c#de
Example Explanation :
In the above example, we provide two parameters for replacing the characters, 1st parameter o is given in the string and 2nd is # you replace in that place.
5. split()
split() function is splits the string at the specified separator and returns a list.
Example 1:
myString = "My name is Yogita".split()
print(myString)
Output :
['My', 'name', 'is', 'Yogita']
Example Explanation :
In the above example, we used split() function for seperate or break the string.
Example 2:
students = "Yogita,Harshada,Anushka,Sakshi"
print(students.split(","))
Output :
['Yogita', 'Harshada', 'Anushka', 'Sakshi']
Example Explanation :
In the above example, you can provide split the string Yogita,Harshada,Anushka,Sakshi into a list of individual names using the comma (",") as the separator.
Example 3:
students = "Yogita#Harshada#Anushka#Sakshi"
print(students.split("#"))
Output :
['Yogita', 'Harshada', 'Anushka', 'Sakshi']
Example Explanation :
In the above example, you can provide split the string Yogita#Harshada#Anushka#Sakshi into a list of individual names using the comma ("#") as the separator.
Array​
Array is collection of similar data types. Array index always starts with the 0 index.
Example :
myString="India"
print(myString[2])
Output :
d
In Python language, an array concept is not available. Array is available in other languages like c, c++, etc.
Escape Charaters​
An escape character is a special character that is used to represent certain sequences of characters that cannot be directly represented in a string. In Python, the backslash (\) is used as the escape character.
Example 1:
sentence = "I'm Yogita."
print(sentence)
Output :
I'm Yogita.
Example Explanation :
In this example, we have assigned the string "I'm Yogita." to the variable sentence. The string is enclosed in double quotes because the sentence itself contains a single quote. The backslash is not needed here because the single quote does not need to be escaped. The print() function is used to display the value of the sentence variable.
Example 2:
sentence = 'I\'m Good. She said, How are you?'
print(sentence)
Output :
I'm Good. She said, How are you??
Example Explanation :
In this example, we have assigned the string 'I'm Good. She said, How are you?' to the variable sentence. The string is enclosed in single quotes because the sentence itself contains a single quote. However, to include the single quote within the string, we need to escape it using the backslash (\). This tells Python to treat the single quote as a literal character and not as the end of the string. The print() function is used to display the value of the sentence variable.
In both examples, the use of escape characters (') allows us to include single quotes within the string without causing syntax errors or prematurely ending the string.