Strings in Python | Python Tutorial - Day #11

Python Tutorial - Day #11: Strings

1. Summary

This video, part of CodeWithHarry's Python tutorial series for beginners, focuses on strings in Python. It revisits the concept of strings as a fundamental data type, demonstrating different ways to define them (using single and double quotes) and exploring string indexing and multi-line strings. The video also introduces the concept of looping through strings using a 'for' loop, although loops themselves are not deeply explained at this stage.

2. Key Takeaways

* **Strings are defined using single or double quotes:** Anything enclosed within single (`'...'`) or double (`"..."`) quotes is a string in Python.

* **Strings are sequences of characters:** You can access individual characters in a string using indexing, starting from 0.

* **Multi-line strings are created using triple quotes:** Use triple single quotes (`'''...'''`) or triple double quotes (`"""..."""`) to define strings that span multiple lines.

* **String Indexing:** Strings can be indexed to access individual characters. The first character is at index 0. Attempting to access an index outside the string's length results in an "IndexError."

* **For Loops in Strings:** The for loop can be used to iterate through the characters of a string.

3. Detailed Notes

* **Introduction**

* The video is part of a 100 Days of Code challenge.

* The topic is "Strings" in Python.

* Review of what strings are (special data type).

* Strings are enclosed in double quotes (" ").

* Today's topics are:

* Different ways to create strings.

* Encouragement to follow the creator on Instagram and tag him in their challenge progress.

* **Defining Strings**

* In Python, anything enclosed in single or double quotes is a string.

* Example: `name = "Harry"` is a string.

* Example: `friend = "Rohan"` is a string.

* Example: `anotherFriend = "Lovish"` is a string.

* Single quotes can also be used: `anotherFriend = 'Lovish'`

* Quoted definition: "In python, anything that you enclose between single or double quotation marks is considered as a string."

* Quoted definition: "A string is essentially a sequence or array of textual data."

* Quoted definition: "Strings are used when working with Unicode Character"

* **String Examples and Use Cases**

* Running the code `name = "Harry"; print("Hello, " + name)` will output "Hello, Harry".

* Strings can use single quotes, as well.

* Example: Printing the phrase "He said I want to eat an apple".

* The string can use single quotes to resolve double quote errors.

* **Error Prevention**

* When including quotes inside a string defined by the same quote type (e.g., double quotes inside a double-quoted string), use escape sequences or change the string's outer quote style.

* **Multi-Line Strings**

* Problem: Creating a multi-line string using regular quotes will cause an error. The error is "EOL (End Of Line) while scanning string literal."

* Solution: Use triple single quotes (`'''...'''`) or triple double quotes (`"""..."""`) to create multi-line strings.

* Example:

```python

string = """Hello Harry

He said "Hi Harry"

Hey I am good"""

print(string)

```

* This is useful for printing blocks of text.

* **String Indexing**

* Strings are like arrays of characters.

* Each character has an index, starting from 0.

* `name = "Harry"`

* H -> index 0

* a -> index 1

* r -> index 2

* r -> index 3

* y -> index 4

* `print(name[0])` will print "H".

* `print(name[1])` will print "a".

* Attempting to access an index outside the string length will raise an "IndexError." (e.g. `name[5]`)

* **Looping Through Strings (Introduction to For Loops)**

* Problem: How to print all characters of a string without explicitly indexing them all.

* Solution: Use a 'for' loop to iterate through the string.

* Example:

```python

name = "Harry"

for character in name:

print(character, end="\n") #Prints each character on a new line

```

* This will print each character of "Harry" on a new line.

* Explanation of the for loop: A "black box" that iterates through each character.

* Note: Loops are not fully explained in this video; a future video will cover them.

* **Next Steps**

* The next video will delve deeper into strings.

* Encouragement to access the Python playlist and the related Replit code.