Transcript Selenium Tutorial Day 7-1

Portnov Computer School
Test Automation For Web-Based Applications
Presenter:
Ellie Skobel
Day 7
Python Basics
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Memory locations reserved to store values
Variables are dynamically typed
Use the equal sign (=) to assign a value to a
my_variable = “hello”
variable
Assign a single value to several variables
a = b = c = 22
simultaneously
Assign multiple values to multiple variables
name, age, height= "Bob", 22, ”5’11"
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Variable names are case-sensitive.
A variable's name can be any legal identifier (an
unlimited-length sequence of Unicode letters and
digits)
Must beginning with a letter or underscore
Variables that start with an underscore (_) are
treated as local and private, and cannot be
imported from outside the module
When choosing a name for your variables, use full
words instead of cryptic abbreviations. This will
make your code easier to read and understand
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Built-in Functions
Definition
dict(iterable)
Create a new dictionary
enumerate(sequence, start=0)
Count and iterate through the sequence
eval(expression)
Compiles and immediately evaluates an
exec(expression)
This statement supports dynamic
execution of Python code.
float(arg), int(arg), str(arg)
Return a float, integer, or string
constructed from the argument
hasattr(object, str_arg_name)
Returns true/false whether an attribute
exists in an object
list(iterable)
Create a new list
expression
View all of the Built-in functions here:
https://docs.python.org/2/library/functions.html
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Built-in Functions
Definition
open(name, mode=r)
Open a file
print(objects, sep=' ')
Print objects to the stream file
range(start, stop[, step])
Create lists containing arithmetic progressions
reversed(seq)
Return a reverse iterator. seq
round(number[, ndigits]) Return the floating point value number
rounded to ndigits digits
sorted(iterable)
Return a new sorted list from the items in
iterable.
zip([iterable, iterable,…]) This function returns a list of tuples
(2 or more dimensional list)
View all of the Built-in functions here:
https://docs.python.org/2/library/functions.html
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Can be concatenated:
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◦ "My name is " + "Jane"
◦ "My name is " + name
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"h"
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Can be sliced:
◦ name = "Geraldine"
◦ name[1:4]
 "era"
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Can be indexed:
◦ name = "John”
◦ name[2]
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Can be measured:
◦ name = "Geraldine"
◦ len(name)
 9
Can be formatted:
name = "JoHn"
name.lower() 
name.upper() 
name.title() 
"john"
"JOHN"
"John”
Can be repeated:
◦ name = "Bob"
◦ name*3
 "BobBobBob"
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Can be reversed:
◦ name = "Geraldine"
◦ name[::-1]
 "enidlareG
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Easy to create:
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◦ my_list = [1,2,3]
◦ names = ["Bob", "Eva"]
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Can be combined:
◦ list = [4,2,6,8,3]
◦ list.sort()[2,3,4,6,8]
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◦ a, b = [1, 2], [6, 7]
◦ a + b  [1, 2, 6, 7]
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Can be indexed:
Can be sliced:
◦ my_list = [1,2,3,4,5]
◦ my_list[1:4:2]  [2,4]
Can be repeated:
◦ list = [1,2,3]
◦ list*2  [1,2,3,1,2,3]
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◦ names = ["Bob", "Eva"]
◦ names[1]
 "Eva"
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Can be sorted:
Can be measured:
◦ list = ["a","b","c"]
◦ len(list)  3
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Can be reversed:
◦ list = [1,2,3,4]
◦ list[::-1]  [4,3,2,1]
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IF
◦ x = 4
◦ if x > 0: print("yes")
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IF / ELSE
◦ x = 4
◦ if x > 0: print("yes")
◦ else: print("no")
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IF / ELIF / ELSE
x = 4
if x > 2:
print("yes")
elif x > 0:
print("still yes")
else:
print(""no)
Conditional assignment
◦ age = 12
◦ name = "Bob" if age > 18 else "Bobby"
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Iterate through a list:
list_of_items = [1,2,3,4]
for item in list_of_items:
print('-> ' + item)
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Iterate x times:
x = 4
for j in range(x):
print('number:', x)
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Iterate and enumerate (count):
->
->
->
->
1
2
3
4
number:
number:
number:
number:
0
1
2
3
item 1 is an apple
item 2 is an orange
items = ["apple", "orange"]
for j, item in enumerate(items):
print("item {0} in an {1}".format(j+1, item))
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break: breaks out of the smallest enclosing loop
loop stops after
for x in range(2, 6):
x=2
if 8 % x == 0:
print 8, 'equals', x, '*', 8/x
break
8 equals 2 * 4
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continue: skips code which follows and continues
with the next iteration of the loop:
x = 4
for j in range(x):
if x % 2 == 0:
3 is an odd number
continue
print x, 'is an odd number'
print statement skipped
for even numbers
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ELSE: a loop’s else clause runs when no break
occurs
for x in ('a', 'b', 'c', 'd'):
pass
PASS statement
does nothing.
else:
print('loop finished')
loop finished
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