Python Basics
Whitespace matters! Your code will not run correctly if you use improper indentation.
#this is a comment
Basic Python Logic
if:
if test:
#do stuff if test is true
elif test 2:
#do stuff if test2 is true
else:
#do stuff if both tests are false
while:
while test:
#keep doing stuff until
#test is false
for:
for x in aSequence:
#do stuff for each member of aSequence
#for example, each item in a list, each
#character in a string, etc.
for x in range(10):
#do stuff 10 times (0 through 9)
for x in range(5,10):
#do stuff 5 times (5 through 9)
Python Strings
A string is a sequence of characters, usually used to store text.
creation:!the_string = “Hello World!”
!!the_string = ‘Hello World!’
accessing:!the_string[4]! ! returns ‘o’
splitting:!the_string.split(‘ ‘)!returns [‘Hello’, ‘World!’]
!!the_string.split(‘r”)!returns [‘Hello Wo’, ‘ld!’]
To join a list of strings together, call join() as a method of the string you want to separate the values in the list (‘’ if
none), and pass the list as an argument. Yes, it’s weird.
words = [“this”, ‘is’, ‘a’, ‘list’, ‘of’, “strings”]
‘ ‘.join(words)!!returns “This is a list of strings”
‘ZOOL’.join(words)!returns “ThisZOOLisZOOLaZOOLlistZOOLofZOOLstrings”
‘’.join(words)! ! returns “Thisisalistofstrings”
String Formatting: similar to printf() in C, uses the % operator to add elements of a tuple into a string
this_string = “there”
print “Hello %s!”%this_string!returns “Hello there!”
Python Tuples
A tuple consists of a number of values separated by commas. They are useful for ordered pairs and returning several
values from a function.
creation: emptyTuple = ()
singleItemTuple = (“spam”,) note the comma!
thistuple = 12, 89, ‘a’
thistuple = (12, 89, ‘a’)
accessing: thistuple[0] returns 12
