Curso python udemy

• Integers are used to represent whole numbers:

  rank = 10
  eggs = 12
  people = 3

• Floats represent decimal numbers:

  temperature = 10.2
  rainfall = 5.98
  elevation = 1031.88

• Strings represent text:

  message = "Welcome to our online shop!"
  name = "John"
  serial = "R001991981SW"

• Lists represent arrays of values that may change during the course of the program:

  members = ["Sim Soony", "Marry Roundknee", "Jack Corridor"]
  pixel_values = [252, 251, 251, 253, 250, 248, 247]

• Dictionaries represent pairs of keys and values:

  phone_numbers = {"John Smith": "+37682929928", "Marry Simpons": "+423998200919"}
  volcano_elevations = {"Glacier Peak": 3213.9, "Rainer": 4392.1}

• Keys of a dictionary can be extracted with:

  phone_numbers.keys()

• Values of a dictionary can be extracted with:

  phone_numbers.values()

• Tuples represent arrays of values that are not to be changed during the course of the program:

  vowels = ('a', 'e', 'i', 'o', 'u')
  one_digits = (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)

• You can get a list of attributes of a data type has using:

  dir(str)
  dir(list)
  dir(dict)

• You can get a list of Python builtin functions using:

  dir(__builtins__)

• You can get the documentation of a Python data type using:

  help(str)
  help(str.replace)
  help(dict.values)

Sometimes you might need to convert between different data types in Python for one reason or another. That is very easy to do:

• From tuple to list:

  cool_tuple = (1, 2, 3)
  cool_list = list(cool_tuple)
  cool_list # [1, 2, 3]

• From list to tuple:

  cool_list = [1, 2, 3]
  cool_tuple = tuple(cool_list)
  cool_tuple # (1, 2, 3)

• From string to list:

  cool_string = "Hello"
  cool_list = list(cool_string)
  cool_list # ['H', 'e', 'l', 'l', 'o']

• From list to string:

  cool_list = ['H', 'e', 'l', 'l', 'o']
  cool_string = str.join("", cool_list)
  cool_string # 'Hello'

As can be seen above, converting a list into a string is more complex. Here str() is not sufficient. We need str.join(). Try running the code above again, but this time using str.join(«—», cool_list) in the second line. You will understand how str.join() works.