• and - use to denote && inclusive of a particular condition • del - delete a value • from - tells python what and where to look for functions • not - exclusive to a particular value, as in "luke, you are NOT my father" • while - run until the condition is no longer true • as - ??? • elif - else if, a serrogate of the if statement • global - global value, the entire app knows this member • or - use to denote || not inclusive as in "either OR" • with - ??? • assert - to assert a statement • else - also known as "otherwise" • if - asks about the status of a condition • pass - keep on truckin' • yield - stop • break - stop the switch right here, right now • except - everything but the value that comes after this statement • import - bring in some functions and modules • print - I want to see the results of this shit • class - a self contained mini python program • exec - execute this code • in - is it in a list or dict? We tell the program what list we want to iterate over • raise - Bring an exception to the front • continue - keep on truckin' • finally - if everything has run, I still want you to ru this • is - is tests for identity, not equality. That means Python simply compares the memory address a object resides in. is basically answers the question "Do I have two names for the same object?" - overloading that would make no sense. • return - Bring me back some shit to work with • def - this is a function intro • try - first try the clause • for - iterate over the items in any sequence... in the order they appear • lambda - lambda functions:
f = lambda x: x**2 + 2*x - 5
Those things are actually quite useful. Python supports a style of programming called functional programming where you can pass functions to other functions to do stuff. Example:
mult3 = filter(lambda x: x % 3 == 0, [1, 2, 3, 4, 5, 6, 7, 8, 9])
sets mult3 to [3, 6, 9], those elements of the original list that are multiples of 3. This is shorter (and, one could argue, clearer) than
def filterfunc(x):
return x % 3 == 0
mult3 = filter(filterfunc, [1, 2, 3, 4, 5, 6, 7, 8, 9])
Of course, in this particular case, you could do the same thing as a list comprehension:
mult3 = [x for x in [1, 2, 3, 4, 5, 6, 7, 8, 9] if x % 3 == 0]
(or even as range(3,10,3)) but there are other cases, like constructing functions as return values from other functions, where you can't use a list comprehension and a lambda function may be the shortest way to write something out. Like
def transform(n):
return lambda x: x + n
f = transform(3)
f(4) # is 7
For data types, write out what makes up each one. For example, with strings write out how you create a string. For numbers write out a few numbers.
• True - if x == True
• False - if b == False
• None -
• strings - print "stuff"
• numbers - 56
• floats - 45.758
• lists - my_list = [1, 2, 3, 5]
• \ - comment • \’ - single quote • " - double quote • \a - ASCII bell • \b - backspace • \f - Form feed • \n - new line • \r - carriage return • \t - tab • \v - vertical tab
• %d - decimal number • %i - integer • %o - octal • %u - unsigned decimal int • %x - hex integer • %X - Hex integer (upper case) • %e - exponential notation (lower case "e") • %E - exponential notation (upper case "E") • %f - floating point number • %F - same • %g - the shorter of %f and %e • %G - same • %c - character • %r - • %s - string • %% - literal %