what are strings?

what are strings?

1. The data type"string" is used to show a piece of text.

   • consists of any character such as
     • symbol
     • punctuation
     • letter

2. common string functions

   • len(string)
     • This will find the total length of the string
   • str(x)

3. strings in Python are arrays of bytes representing unicode characters.

   • a single character is simply a string with a length of 1

4. types of string operators

   • Arithmetic operators, Assignment operators, Comparison operators, Logical operators, Identity operators, Membership operators

5. computing in 9G

   • lists
     • written with square brackets [ ]
     • A list is a collection which is ordered and changeable
     • thislist = ["apple", "banana", "cherry"] thislist.remove("banana") print(thislist)
     • #0=apple 1=banana 2=cherry thislist = ["apple","banana","cherry"] print(thislist(1))
     • thislist = ["apple", "banana", "cherry", "orange", "kiwi", "melon", "mango"] print(thislist[2:5])
   • connectivity
     • the state of being connected or interconnected
     • cables in the ocean
     • bandwidth
       • the amount of data that can be carried at a time
         • like the amount of water can be carried down a single pipe at a time
       • is measured in bits per second
     • connection speed
       • megabits per second (mbps)
       • 108 mbps-download
         • 10mbps-upload
           • there are more people are download items on the internet rather than upload.companies anticipate this so they make a deal
       • what is the difference between fiber optic and copper cable
         • The reason fiber optic cable is faster is because of the extremely high frequency ranges it is able to carry, whereas signal strength diminishes at high frequencies with copper wire. Fiber optic cable can carry more than a thousand times the bandwidth of copper cable and go more than one hundred times further as well
     • broadband
       • highspeed connection to the internet that has super sede the use of dial up connection
       • name size byte
         • Bit(b) 0/1 ...
           • nibble 4 bits ...
             • Byte(B) 8bits ...
               • Kilobyte (KB) 8,000bits 1000bytes
                 • Megabyte (MG) 8,000,000bits 1000kilobytes
                   • Gigabyte (GB) 8,000,000,000bits 1000 (GB)
                     • Terabyte (TB) 8,000,000,000,000 bits 1000 (TB)
                       • Petabyte (PB) 8,000,000,000,000,000 1000 (PB)
     • calculating speed
       • 1MB file at 8MBPs=8MB at 8Mbps=1 second
     • copper cable fiber opytic
       • cheap expensive
         • slow fast
           • thick thin
     • wireless conection
       • advantage
         • connect to phone
         • cheap
         • easy to install
         • mobile can move
       • wifi
       • disadvantage
         • less secure
           • interference
     • buffering
       • buffering occurs when a movie track plays faster than it downloads
   • networks
     • World Wide Web: a collection of web pages on the Internet
     • Internet: a global network of networks Note. THE WORLD WIDE WEB IS NOT THE INTERNET!!!!!! The internet can be used without using the WWW e.g. email and instant messaging
     • Network: a group or system of interconnected people or things
     • URLS and web addresses: URL (Uniform Resource Locator) = the address of a web page.
     • Data transfer: Data is separated into data packets which contain the destination and the sender’s address as well as instructions on how to reassemble.
       • It can be transported in two different ways: Circuit switching: All packets follow the same, shortest route. This means it is easier to reassemble but more vulnerable to be intercepted by a hacker. Packet Switching: All packets take different routes. Harder to reassemble but safer.