Python 3 cheatsheet (the basics)                                                                                                                            GROK
                                                                                                                                                               LEARNING
    Interact with the user (input and output)                                                 Text (strings)                               Variables
       Print a message                                                                           Single quoted                                Creating a variable
         print('Hello, world!')                                                                    'perfect'                                    celsius = 25
       Print multiple values (of different types)                                                Double quoted                                Using a variable
         ndays = 365                                                                               "credit"                                     celsius*9/5 + 32
         print('There are', ndays, 'in a year')
                                                                                                 Multi-line
       Asking the user for a string                                                                '''Hello,
         name = input('What is your name? ')                                                       World!'''                               Whole numbers (integers)
       Asking the user for a whole number (an integer)                                           Add (concatenate) strings                    Addition and subtraction
         num = int(input('Enter a number: '))                                                      'Hello' + 'World'                            365 + 1 - 2
                                                                                                 Multiply string by integer                   Multiplication and division
    Decide between options                                                                         'Echo...'*4                                  25*9/5 + 32
       Decide to run a block (or not)            Are two values equal?                           Length of a string                           Powers (2 to the power of 8)
         x = 3                                     x == 3                                          len('Hello')                                 2**8
         if x == 3:                              ⾠ two equals signs, not one
           print('x is 3')                                                                       Convert string to integer                    Convert integer to string
       Decide between two blocks                 Are two values not equal?                         int('365')                                   str(365)
         mark = 80                                 x != 3
         if mark >= 50:                          Less than another?                           Repeat a block (a fixed number of times)
           print('pass')
         else:                                     x < 3                                         Repeat a block 10 times                   Count from 0 to 9
           print('fail')
                                                 Greater than another?                             for i in range(10):                       range(10)
       Decide between many blocks                  x > 3                                             print(i)                              ⾠ range starts from 0 and goes
         mark = 80                                                                               Sum the numbers 0 to 9                           up to, but not including, 10
         if mark >= 65:                          Less than or equal to?
           print('credit')                         x <= 3                                          total = 0
         elif mark >= 50:                                                                          for i in range(10):                     Count from 1 to 10
           print('pass')                         Greater than or equal to?                           total = total + i                       range(1, 11)
         else:                                                                                     print(total)
           print('fail')                           x >= 3                                                                                  Count from 10 down to 1
       ‣elif can be used without else                                                            Repeat a block over a string
                                                 The answer is a Boolean:                          for c in 'Hello':                         range(10, 0, -1)
       ‣elif can be used many times                True            or    False                       print(c)                              Count 2 at a time to 10
                                                                                                 Keep printing on one line                   range(0, 11, 2)
    String manipulation                                                                            for c in 'Hello':                       Count down 2 at a time
                                                                                                     print(c, end=' ')
       Compare two strings                       Convert to uppercase                              print('!')                                range(10, 0, -2)
         msg = 'hello'                            msg.upper()                                    Repeat a block over list (or string) indices
         if msg == 'hello':                      also lower and title
           print('howdy')                                                                          msg = 'I grok Python!'
                                                 Count a character in  a string                    for i in range(len(msg)):
       Less than another string?                                                                     print(i, msg[i])
         if msg < 'n':                            msg.count('l')
           print('a-m')                          Replace a character or string                Putting it together: Celsius to Fahrenheit converter
         else:
           print('n-z')                           msg.replace('l','X')                           Ask the user for a temperature in degrees Celsius
       ⾠ strings are compared character Delete a character or string                               celsius = int(input('Temp. in Celsius: '))
              at a time (lexicographic order)     msg.replace('l','')
       Is a character in a string?                                                               Calculate the conversion
         'e' in msg                              Is the string all lowercase?                      fahrenheit = celsius*9/5 + 32
       Is a string in another string?             msg.islower()                                  Output the result
         'ell' in msg                            also isupper and istitle                          print(fahrenheit, 'Fahrenheit')
         s = [datetime.
        hs.insert(0, lamb
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       self.format = format
   def __getitem__(self, i):
       funcs = self._months[i]
       if isinstance(i, slice)
           return [f(self.for
       else:
           return funcs(sel     Learn more in Intro. to Programming @ groklearning.com
           n__(self):