Strings Variables Lists Tuples Dictionary Control Function Files Exceptions OOP Algorithm Data Structure back
Assignment - Value
- Process of storing a value inside a variable is called assignment.
- Every variable is connected to a value.
- The assignment operator (“=” symbol) is assigning value(s) to a variable.
variablename = value(s)
Variable Naming Restrictions
- no keywords
- No spaces
- Start with letter of underscores
- Only letters, numbers and underscore
- Case sensitive
- lowercase,
- contain only letters, numbers, and underscores,
- short and descriptive.
Examples
message = "This is a message."
print(message)
# OUTPUT
# This is a message.
# Multiple assignment
x,y,z = 1,2,3
- Data Types
print(type("a")
<class 'str'>
print(type(2)
<class 'int'>
print(type(2.5)
<class 'float'>
Expression
- is a combination of numbers, symbols or other variables that produce a result when evaluated.
CASTING Implicit vs Explicit Conversion
Implicit conversion
is where the interpreter helps us out and automatically converts one data type into another, without having to explicitly tell it to do so.
Explicit conversion
is where we manually convert from one data type to another by calling the relevant function for the data type we want to convert to.
print("2 + 2 = " + str(2 + 2))
we needed to call the str() function to convert the number into a string.
Base = 6
Height = 3
Area = (base*height)/2
print("the area of the triangle is: " + str(area))
user input
name = input("what is your name? ")
print(name)
#OUTPUT
#the name
luckynumber = int(input("Enter a number? "))
print(luckynumber)
#OUTPUT
#the luckynumber
Print methods - f-string
first_name = "Mike"
last_name = "O'Neill"
full_name = f"{first_name} {last_name}"
print(full_name.title())
# OUTPUT
#
methods for printing
full_name = f"{first_name} {last_name}"
print(full_name.upper())
print(full_name.lower())
# OUTPUT
#
more methos
first_name = "Mike"
last_name = "O'Neill"
full_name = f"{first_name} {last_name}"
print(f"Hello, {full_name.title()}!")
# OUTPUT
#
or
first_name = "Mike"
last_name = "O'Neill"
message = f"Hello, {full_name.title()}!"
print(message)
# OUTPUT
#
or
first_name = "Mike"
last_name = "O'Neill"
full_name = "{} {}".format(first_name, last_name)
print(full_name)
# OUTPUT
#
Whitespace, Tabs and Newlines
print("Python")
print("\tPython")
print("Languages:\nC++\Java\nbash\tPython")
# OUTPUT
# Python
String methods
| Method | Description |
|---|---|
| casefold() | Converts string into lower case |
| capitalize() | Converts string into capitalized case |
| center() | Returns a centered string |
| count() | Returns the number of times a specified value occurs in a string |
| encode() | Returns an encoded version of the string |
| endswith() | Returns true if the string ends with the specified value |
| expandtabs() | Sets the tab size of the string |
| find() | Searches the string for a specified value and returns the position of where it was found |
| format() | Formats specified values in a string |
| format_map() | Formats specified values in a string |
| index() | Searches the string for a specified value and returns the position of where it was found |
| isalnum() | Returns True if all characters in the string are alphanumeric |
| isalpha() | Returns True if all characters in the string are in the alphabet |
| isdecimal() | Returns True if all characters in the string are decimals |
| isdigit() | Returns True if all characters in the string are digits |
| isidentifier() | Returns True if the string is an identifier |
| islower() | Returns True if all characters in the string are lower case |
| isnumeric() | Returns True if all characters in the string are numeric |
| isprintable() | Returns True if all characters in the string are printable |
| isspace() | Returns True if all characters in the string are whitespaces |
| istitle() | Returns True if the string follows the rules of a title |
| isupper() | Returns True if all characters in the string are upper case |
| join() | Joins the elements of an iterable to the end of the string |
| ljust() | Returns a left justified version of the string |
| lower() | Converts a string into lower case |
| lstrip() | Returns a left trim version of the string |
| maketrans() | Returns a translation table to be used in translations |
| partition() | Returns a tuple where the string is parted into three parts |
| replace() | Returns a string where a specified value is replaced with a specified value |
| rfind() | Searches the string for a specified value and returns the last position of where it was found |
| rindex() | Searches the string for a specified value and returns the last position of where it was found |
| rjust() | Returns a right justified version of the string |
| rpartition() | Returns a tuple where the string is parted into three parts |
| rsplit() | Splits the string at the specified separator, and returns a list |
| rstrip() | Returns a right trim version of the string |
| split() | Splits the string at the specified separator, and returns a list |
| splitlines() | Splits the string at line breaks and returns a list |
| startswith() | Returns true if the string starts with the specified value |
| strip() | Returns a trimmed version of the string |
| swapcase() | Swaps cases, lower case becomes upper case and vice versa |
| title() | Converts the first character of each word to upper case |
| translate() | Returns a translated string |
| zfill() | Fills the string with a specified number of 0 values at the beginning |