Basics 12/01 - Strings

# # Expressions Vs Statements

# iq = 100 # this entire line is a statement

# user_age = iq / 5 # "iq / 5" is an expression, that produces a value. In this case the expression is within a statement

# # a statement is an entire line of code that performs an action, in the above case the entire line is a statement

# # Augmented Assignment Operator

# # some_value = 5

# # some_value = some_value + 2

# # some_value += 2 # shorthand version of the above. To work the variable requires a pre-existing value

# # # works with several operators e.g +,-,*,/ - these go to the left of the = sign

# # # print(some_value)

# # Strings - Str - a string is simply a line of text

# "such as this,"

# 'or this! You can even put numbers like 73 in it!'

# # for individual variables on a single line

# username = 'stinkycoder'

# password = 'goongaginga'

# # triple quotes for strings that cover multiple lines of text

# long_string = '''

# WOW

# O O

# ___

# '''

# # print(long_string)

# first_name = 'bob'

# last_name = 'billy'

# full_name = first_name + ' ' + last_name # the additional quotes allow for a space between names

# print(full_name)

# # String Concatenation - simply, adding strings together

# print('hello' + 'bob') # only works between strings, e.g. could not do hello + 5 like this

#type conversion

# print(type(str(100))) # 100 has been converted into a string

# print(type(int(str(100)))) # 100 has been converted into a string, then back to an int

# a = str(100)

# b = int(a)

# c = type(b)

# print(c) # performs same function as our previous conversion, using variables

# # Escape Sequence - issues with double quotes and similar

# # weather = "it's "kind of" sunny" - situations like this don't work

# weather = "\it\'s \"kind of\" sunny" # using backslash \ allows python to see that this is a full string

# # other special functions: \t creates a tab spacing effect, \n creates a new line

# print(weather)

#Formatted strings - for more dynamic situations e.g. changing names etc

#name = 'Jimbo'

#age = '73'

# print('Hi' + ' ' + name + '. You are ' + str(age) + ' years old!') # works but is extremely clunky

# print(f'hi {name}. You are {age} years old.') # significantly cleaner version using f to denote formatting, and {} for variables

# print('hi {}. You are {} years old.'.format(name, age)) # alternative method - using numbers from 0 can change rotation of info

# print('hi {new_name}. You are {age} years old.'.format(new_name = 'sally', age = 100)) # also works

#.format slightly more complicated to deal with than just using f at the start of a string, but may be common in older code

# # String Indexes

# selfish = 'me me me'

# #01234567 # each shelf corresponds to a value in the sting, e.g 0 = m, 1 = e, 3 = space etc

# print(selfish[0]) # this will print the letter "m", by finding the data indexed at that point in the string

# # [start] first item in the brackets is the start of the search

# # [start:stop] allows you to set a place to end the search as well

# print(selfish[0:4]) # prints items 0-4 in the variable, in this case "me m"

# # [start:stop:stepover] stepover allows you to skip a certain number

# print(selfish[0:8:2]) # in this case the step is 2, so it will skip every second item

# print(selfish[-1]) # this will effectively start at the end and work backwards, e.g. here it will start at "e" which is 7th

# print(selfish[::-1]) # this will entirely reverse the string, on higher numbers will skip as usual backwards instead

# Immutability - cannot be changed. Strings are immutable. The only way to change it is to completely reassign variable