# 1
What suffix do Python source files have?
.py
Name the Python source file ex1
ex1.py
How would one execute ex1.py?
python ex1.py
Is this correct?
print "Hello World!"
yes
Is this correct?
print "Hello World!'
no
Is this correct?
print 'Hello World!'
yes
Is this correct?
print "I'd much rather you 'not'."
yes
Is this correct?
print 'I'd much rather you "not".'
no
Is this correct?
print 'I "said" do not touch this.'
yes
Is this correct?
print 'I\'d much rather you "not".'
yes
Is this correct?
print 'I\'d much rather you \"not\".'
yes
Is this correct?
print 'I'd much rather you \"not\".'
no
Evaluate:
print "Hello World!"
Hello World!
Evaluate:
print "Hello Again"
Hello Again
Evaluate:
print "I like typing this."
I like typing this.
Evaluate:
print "This is fun."
This is fun.
Evaluate:
print 'Yay! Printing.'
Yay! Printing
Evaluate:
print "I'd much rather you 'not'."
I'd much rather you 'not'.
Evaluate:
print 'I "said" do not touch this.'
I "said" do not touch this.
# 2
Python comments are...?
anything following a '#'
Evaluate:
print "I could have code like this." # comment
# print "This won't run."
I could have code like this.
Evaluate:
# print "I could have code like this." # comment
# print "This will run."
(nothing)
# 3
Evaluate:
print "I will now count my chickens:"
I will now count my chickens:
Evaluate:
print "Hens", 25 + 30 / 6
Hens 30
Correct?
print "Hens" 25 + 30 / 6
no; SyntaxError: invalid syntax
Correct?
print "Hens", 25 + 30 / 6,
yes
Evaluate:
print "Hens", 25 + 30 / 6,
Hens 30
Correct?
print "Hens", (25 + 30 / 6)
yes
Evaluate:
print "Roosters", 100 - 25 * 3 % 4
Roosters 97
Evaluate:
print "Roosters", 100 - 25 * 3 % 4
Roosters 97
Evaluate:
print "Roosters", 100 - 25 * (3 % 4)
Roosters 25
Evaluate:
print "Roosters", 100 - (25 * 3 % 4)
Roosters 97
Evaluate:
print "Roosters", 100 - (25 * 3) % 4
Roosters 97
Evaluate:
print "Now I will count the eggs:"
Now I will count the eggs:
Evaluate:
print 3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6
7
Evaluate:
print "Is it true that 3 + 2 < 5 - 7?"
Is it true that 3 + 2 < 5 - 7?
Evaluate:
print 3 + 2 < 5 - 7
False
Evaluate:
print "What is 3 + 2?", 3 + 2
What is 3 + 2? 5
Evaluate:
print "What is 5 - 7?", 5 - 7
What is 5 - 7? -2
Evaluate:
print "Oh, that's why it's False."
Oh, that's why it's False.
Evaluate:
print "How about some more."
How about some more.
Evaluate:
print "Is it greater?", 5 > -2
Is it greater? True
Evaluate:
print "Is it greater or equal?", 5 >= -2
Is it greater or equal? True
Evaluate:
print "Is it less or equal?", 5 <= -2
Is it less or equal? False
Evaluate:
25 + 30 / 6
30
Evaluate:
25 + (30 / 6)
30
Evaluate:
100 - 25 * 3 % 4
97
Evaluate:
100 - 25 * (3 % 4)
25
Evaluate:
100 - 25.0 * (3 % 4)
25.0
Evaluate:
100 - 25.0 * 3 % 4
97.0
Evaluate:
100 - 25 * 3 % 4.0
97.0
Evaluate:
30 / 7
4
Evaluate:
30.0 / 7
4.2857142857142856
Evaluate:
30 / 7.0
4.2857142857142856
Correct?
true & true
no
Correct?
true & True
no
Correct?
True & True
yes
Evaluate:
true
error: NameError: name 'true' is not defined
Evaluate:
True
True
Evaluate:
False
False
Evaluate:
false
error: NameError: name 'false' is not defined
# 4
Correct?
cars_driven = 30
space_in_a_car = 4.0 # comment
carpool_capacity = cars_driven * space_in_a_car
print "We can transport", carpool_capacity, "people today."
yes
Evaluate:
cars_driven = 30
space_in_a_car = 4.0 # comment
carpool_capacity = cars_driven * space_in_a_car
print "We can transport", carpool_capacity, "people today."
We can transport 120.0 people today.
Evaluate:
var = 2
var = 4
print var
4
Evaluate:
cars_driven = 30
space_in_a_car = 4 # comment
carpool_capacity = cars_driven * space_in_a_car
print "We can transport", carpool_capacity, "people today."
We can transport 120 people today.
Evaluate:
cars_driven = 30
space_in_a_car = 4 # comment
carpool_capacity = cars_driven * space_in_a_car
print "We can transport" carpool_capacity "people today."
error; SyntaxError: invalid syntax
Correct?
cars = 100
print "There are", cars, "cars available."
yes
Correct?
val cars = 100
print "There are", cars, "cars available."
no
Correct?
int cars = 100
print "There are", cars, "cars available."
no
Correct?
int cars = 100;
print "There are", cars, "cars available.";
no
Correct?
cars = 100
print "There are", cars, "cars available.";
yes
Correct?
cars = 100;
print "There are", cars, "cars available.";
yes
Evaluate:
space_in_a_car = 4.0 # why 4.0?
drivers = 10
carpool_capacity = drivers * space_in_a_car
print "We can transport", car_pool_capacity, "people today."
error; NameError: name 'car_pool_capacity' is not defined
# 5
Evaluate:
my_name = 'Zed A. Shaw'
print "Let's talk about %s." % my_name
Let's talk about Zed A. Shaw.
Evaluate:
my_name='Zed A. Shaw'
print "Let's talk about %s." % my_name
Let's talk about Zed A. Shaw.
Evaluate:
my_name="Zed A. Shaw"
print "Let's talk about %s." % myname
Traceback (most recent call last):
File "", line 1, in
NameError: name 'myname' is not defined
Evaluate:
my_name = 'Zed A. Shaw'
print "Let's talk about %my_name."
Let's talk about %my_name.
Evaluate:
my_weight = 180
print "He's %s pounds heavy" % my_weight
He's 180 pounds heavy
Evaluate:
my_weight = 180
print "He's %d pounds heavy" % my_weight
He's 180 pounds heavy
Evaluate:
my_eyes = 'Blue'
my_hair = 'Brown'
print "he's got %s eyes and %s hair" % (my_eyes, my_hair)
he's got Blue eyes and Brown hair
Evaluate:
my_eyes = 'Blue'
my_hair = 'Brown'
print "he's got %s eyes and %s hair" % {my_eyes, my_hair}
Traceback (most recent call last):
File "", line 1, in
TypeError: not enough arguments for format string
Evaluate:
my_eyes = 'Blue'; my_hair = 'Brown'
print "he's got %s eyes and %s hair" % (%my_eyes, %my_hair)
File "", line 1
print "he's got %s eyes and %s hair" % (%my_eyes, %my_hair) ^
SyntaxError: invalid syntax
Evaluate:
my_age=35; my_weight=180; my_height=74
print "If I add %d, %d, and %d I get %d" % (my_age, my_height, my_weight, my_age + my_height + my_weight)
If I add 35, 74, and 180 I get 289
Evaluate:
my_age=35; my_weight=180; my_height=74
print "If I add %d, %d, and %d I get %d" % (my_age, my_height, my_weight, (my_age + my_height + my_weight))
If I add 35, 74, and 180 I get 289
Evaluate:
my_age=35; my_weight=180; my_height=74
print "If I add %a, %b, and %c, I get %d" % (my_age, my_height, my_weight, (my_age + my_height + my_weight))
Traceback (most recent call last):
File "", line 1, in
ValueError: unsupported format character 'a' (0x61) at index 10
Evaluate:
my_height = 180
print "He's %d% inches tall." % my_height
error
Evaluate:
my_height = 180
print "He's %d% inches tall." % (my_height)
error
Evaluate:
my_weight = 180
print "He's %d pounds heavy." % my_weight
He's 180 pounds heavy.
Evaluate:
my_eyes = 'Blue'; my_hair = "Brown"
print "He's got %s eyes and %s hair." % (my_eyes, my_hair)
He's got Blue eyes and Brown hair.
Evaluate:
my_teeth='White'; print "His teeth are usually %s depending on the coffee." % my_teeth
His teeth are usually White depending on the coffee.
Evaluate:
my_age = 35
my_height = 74
my_weight = 180
print "If I add %d, %d, and %d I get %d." % (my_age, my_height, my_weight, my_age + my_height + my_weight)
If I add 35, 74, and 180 I get 289.
Evaluate:
print "he's %d feet tall" % 10.0
he's 10 feet tall
Evaluate:
print "he's %r feet tall" % 10.0
he's 10.0 feet tall
Evaluate:
print "he's %s feet tall" % 10.0
he's 10.0 feet tall
# 6
Evaluate:
w = "This is the left side of..."
e = "a string with a right side."
print w + e
This is the left side of...a string with a right side.
Evaluate:
w = "This is the left side of..."
e = "a string with a right side."
print w ++ e
Traceback (most recent call last):
File "", line 1, in
TypeError: bad operand type for unary +: 'str'
Evaluate:
print "This is the left side of..." + "a string with a right side."
This is the left side of...a string with a right side.
Evaluate:
print ("This is the left side of..." + "a string with a right side.")
This is the left side of...a string with a right side.
Evaluate:
x = "There are %d types of people." % 10
print "I said: %r." % x
I said: 'There are 10 types of people.'.
Evaluate:
x = "There are %d types of people." % 10
print "I said: '%r'." % x
I said: ''There are 10 types of people.''.
Evaluate:
binary = "binary"
do_not = "don't"
y = "Those who know %s and those who %s." % (binary, do_not)
print "I also said: '%s'." % y
I also said: 'Those who know binary and those who don't.'.
Evaluate:
hilarious = False
joke_evaluation = "Isn't that joke so funny?! %r"
print joke_evaluation % hilarious
Isn't that joke so funny?! False
# 7
Nothing new.
# 8
Evaluate:
formatter = "%r %r %r %r"
print formatter % (1, 2, 3, 4)
1 2 3 4
Evaluate:
formatter = "%r %r %r %r"
print formatter % ("one", "two", "three", "four")
'one' 'two' 'three' 'four'
Evaluate:
formatter = "%r %r %r %r"
print formatter % (True, False, False, True)
True False False True
Evaluate:
formatter = "%r %r %r %r"
print formatter % (formatter, formatter, formatter, formatter)
'%r %r %r %r' '%r %r %r %r' '%r %r %r %r' '%r %r %r %r'
Evaluate:
formatter = "%r %r %r %r"
print formatter % (
"I had this thing.",
"That you could type up right.",
"But it didn't sing.",
"So I said goodnight."
)
'I had this thing.' 'That you could type up right.' "But it didn't sing." 'So I said goodnight.'
# 9