Variables and strings

Naming restrictions

• should be assigned before they can be used
• variables have to start with a letter or underscore
• the rest should be letters, numbers, or underscores
• case sensitive
• Conventions
  • lower_snake_case (underscores bet. words)
  • variables should be lower case (except constants)
  • UpperCamelCase usually refers to a class
  • Variables that start and end with two underscores are supposed to be private or left alone
• Double vs string quotes
  • Doesn’t matter but just be consistent throughout the same file
  • Just a stylistic thing
• None
  • special value None
  • represent nothingness (python’s version of null)

 
# None leuwprd
a = None
type(child) # NoneType

Escape characters/sequences

new_line = "hello \nworld"
print(new_line)
#hello
#world
 
s = "backlast : \\"
print(s) #"backslash: \"
 
s = "I said \"ha ha\"" #just use ' inside or vise versa
print(s) # "I said "ha ha""

String concatenation

• Need to be working with strings

print("h" + "i") # "hi"
str1 = "ice"
str1 += " cream" #str1 is "ice cream"

String formatting

• String interpolation: inserting variables, expressions, or values into a string
• f strings
  • print("f{sample_variabele}")

greeting = "hi"
name = "heisenberg"
greet_name = f"{greeting} {name}"

Strings and Indexes

• String is an iterable, and you can access individual chars with indexes
  • Like lists and tuples

name = "Chuk"
name[0] # "C"