me = "Caleb"

#escape character example

print("\n")

me = "C\ta\tl\te\tb\n"

print(me)

#can also use single quotes

you = 'Subscriber'

me = "Caleb" #reset to normal

#passing multiple arguments to print

print(me, you) #output: Caleb Subscriber

#double quotes and single quotes work the same way with the exception of working with quotes inside.

#here are some examples:

single_quotes = 'She said "Hi"'

print(single_quotes) #output: She said "Hi"

double_quotes = "She said \"Hi\""

print(double_quotes) #output: She said "Hi"

single_quotes = 'I\'m learning!'

print(single_quotes) #output: I'm learning!

#notice we have to escape the same quote as the surrounding quote

#this is the same as:

#single_quotes = 'I\'m learning!' #output: I'm learning

double_quotes = "I'm learning!"

print(double_quotes)

#notice we have to escape the same quote as the surrounding quote

#Here are the other escape sequences:

#https://docs.python.org/2.0/ref/strings.html

#Notice that if you want to print \ you must put two

print("\\") #output: \

#This is because \ is an escape character.

#If you want to print a single quote, you can use double quotes to surround it

#or escape it with a backslash

#If you want to print a double quote, you can use single quotes to surround it

#you can also prefix with r which will make a raw string (ignoring escapes except same quote)

print(r'as raw as I\'ve ever seen. \/\/ () \/\/. \t' ) #only \' is escaped

#output: as raw as I've ever seen. \/\/ () \/\/. \t

#This is useful for regex and file paths.

#https://docs.python.org/3/reference/lexical_analysis.html#string-literal

#https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals

########## CONCATENTATION ##########

#Use a + to concatenate

msg = me + " + " + you

print(msg)

#Can use comma separated values in print. Automatically uses spaces between

print(me, "+", you)

#You can automatically concatenate literals (actual values with quotes as opposed to variables)

#by putting them one after the other. This is ideal if you need to split a large string up

#onto multiple lines.

print("my " "name "

"is " "Caleb")

#You can also use multiline string

print("""Name: Caleb

Age: 58""")

#skip newline using \ (without it, it would go down a line each line)

print("""\

Name: Caleb. \

Age: 58""")

"""You may see

them as multi-

line comments even

if they technically

are not.

https://stackoverflow.com/questions/7696924/is-there-a-way-to-create-multiline-comments-in-python

"""

########## INDEXES ##########

#It's very common to grab particular characters within a string

#this is also common for collections when we get to em.

msg = "This is a very important message."

print(msg[5])

#indexing is zero based. This means 0 will get the very first character:

print(msg[0])

#This value is returned and can be assigned to a variable or used in an expression

first_letter = msg[0]

print(first_letter + "acos")

#You can also index from the right.

period = msg[32] #from left

print(period)

period = msg[-1] #from right

print(period)

#This may be obvious, but we do not use -0 to get the first element from the right as we would

#use 0 to get the first element from the left. (Side note) -0 actually is 0:

print(-0) #(side note)

print(0 == -0) #0 == 0 (side note)

########## SLICING #########

#repeating this for ease of reading:

msg = "This is a very important message."

#We can pass two numbers in for the index to get a series of characters.

#left is included. Right is excluded.

#this will get 2 characters (from index 1 - 3 with 3 not included...we are left with index 1 and 2.

print(msg[1:3]) #hi

#You can also leave off first to start at beginning

#or leave off second to go to end

print(msg[:5]) #print index 0-4 (because 5 is excluded, remember)

print (msg[1:]) #from index 1 to end

#We can also use negatives. Here is how you get the last 8 characters:

print(msg[-8:]) #start 8 from right and go to end

#out of range index

#Grabbing an out of range index directly will cause an error.

#But incorrect ranges fail gracefully.

#print(msg[42]) #doesn't work

print(msg[42:43]) #works

########## IMMUTABILITY ##########

#Strings are immutable, meaning they can't change.

cant_change = "Java is my favorite!"

#cant_change[0] = K .....nope. Sorry Kava (my dog)

#generate new string from old:

#Kava is my favorite!

new = 'K' + cant_change[1:]

print(new)

#Python is my favorite!

fav_language = "Python " + cant_change[5:]

print(fav_language) #output: Python is my favorite!

#Java is actually coffee

coffee = cant_change[:8] + "actually coffee" #grab first 7 characters (index 8 not included)

print(coffee) #output: Java is actually coffee

#operations that appear to change string actually replace:

#Java is actually coffee (contrary to popular belief).

coffee += " (contrary to popular belief)."

print(coffee) #output: Java is actually coffee (contrary to popular belief).

########## GETTING STRING LENGTH ##########

#There is a function we can use....

#similar to how we invoke print to do something for us (output to console)

#we can invoke len to count for us:

print(len(coffee)) #output: 43

#for those from other languages...

#notice we do not say coffee.len()

#coffee.len() XXXXXX

#nope.

#last index is always len() - 1.

name = "Caleb"

print("index 4:", name[4]) #b

print("len(name)", len(name)) #length is 5

########## MORE STRING WORK ##########

#How to convert a number to a string

length = len(name)

print("Length is " + str(length)) #output: Length is 5

#this works however sometimes you just need one combined string instead of components.

#when we use a comma, we are passing in data as separate arguments.

#fortunately, print knows how to handle it. Other times, we must pass in one string.

#WARNING --> Commas automatically print a space.

print("length is ", length)

#an example of this is if we need a variable. We cannot use a comma:

#BAD

msg = "length is", len(name)

print(msg) #NOT WHAT WE WANTED!

#output: length is 5 ^ not what we wanted do below instead

#GOOD

length = len(name)

msg = "length is " + str(length)

print(msg) #output: length is 5

#EVEN BETTER

#We can also nest function calls:

print("length is " + str(len(name)))

#The order in which these are invoked are in to out...

#len(name) is first which returns a number.

#this number is passed to str which converts it to a string

#this string is then concatenated with the string on the left

#this final string is then passed to print

#That's the end of your introduction to strings!