newbie: Syntax error

[Chad Everett]

Hi Everyone,

I am new to Python and programming in general. I bought the book "Python
Programming for the Absolute Beginner" by michael Dawson.

I have been working through it but am having trouble.
I am trying to make a coin flip program and keep geting a Synax Error
"invalid syntax".

If anyone has a moment could you please look at it and tell me what I am
doing wrong.

thanks for your time and patience.

Chad

# Coin Flip Program
# This program flips a coin 100 times and tells the number of heads and
tails.
# Chad Everett 2/3/2005


print "\t\t********Coin Flip Game*********\n"
import random

# heads = 1
# tails = 2

tries = random.randrange(2) + 1
count = 1

while count != 100:
if tries == 1:
heads = 1
count += 1

else tries == 2: # I AM GETTING THE SYNTAX ERROR HERE
tails = 1
count += 1

print "heads: " + heads
print "tails: " + tails

raw_input("Press enter to quit")

 

[Kartic]

Chad,

The usage is like this:
- if <cond1>:
- <block 1>
- elif <cond2>:
- <block 2>
- else:
- <block 3>

So, your code should be:
if tries == 1:
.....
elif tries == 2:
.....

(You have 'else' followed by a condition...hence a syntax error. else
is what it means - "if no other condition is satisfied". You should use
'elif' for subsequent conditions after 'if'.)

Thanks,
-Kartic

 

[Matt]

Hi Everyone,

I am new to Python and programming in general. I bought the book "Python
Programming for the Absolute Beginner" by michael Dawson.

I have been working through it but am having trouble.
I am trying to make a coin flip program and keep geting a Synax Error
"invalid syntax".

If anyone has a moment could you please look at it and tell me what I am
doing wrong.

thanks for your time and patience.

Chad

# Coin Flip Program
# This program flips a coin 100 times and tells the number of heads and
tails.
# Chad Everett 2/3/2005


print "\t\t********Coin Flip Game*********\n"
import random

# heads = 1
# tails = 2

tries = random.randrange(2) + 1
count = 1

while count != 100:
if tries == 1:
heads = 1
count += 1

else tries == 2: # I AM GETTING THE SYNTAX ERROR HERE
tails = 1
count += 1

print "heads: " + heads
print "tails: " + tails

raw_input("Press enter to quit")

Chad,

The problem is that you have the statement "tries == 2" after "else".
The proper syntax is:

elif tries == 2: # note "elif"
tails = 1
count += 1

Here's an example of if/elif/else statements in Python:
http://www.network-theory.co.uk/docs/pytut/tut_21.html

Enjoy learning!

 

[F. Petitjean]

Le Fri, 4 Feb 2005 12:49:51 -0600, Chad Everett a écrit :

Hi Everyone,

I am new to Python and programming in general. I bought the book "Python
Programming for the Absolute Beginner" by michael Dawson.

I am trying to make a coin flip program and keep geting a Synax Error
"invalid syntax".

If anyone has a moment could you please look at it and tell me what I am
doing wrong.

thanks for your time and patience.

Chad

# Coin Flip Program
# This program flips a coin 100 times and tells the number of heads and
tails.
# Chad Everett 2/3/2005


print "\t\t********Coin Flip Game*********\n"
import random

# heads = 1
# tails = 2

tries = random.randrange(2) + 1
count = 1

while count != 100:
if tries == 1:
heads = 1
count += 1

else tries == 2: # I AM GETTING THE SYNTAX ERROR HERE

elif tries == 2: # should be better

 

[Bill Mill]

Chad,

try "elif tries == 2" or just "else:". You are not allowed to put an
expression after an else statement.

I recommend you read the python tutorial at
http://docs.python.org/tut/tut.html .

Peace
Bill Mill
bill.mill at gmail.com

 

[John Machin]

Hi Everyone,

I am new to Python and programming in general. I bought the book "Python
Programming for the Absolute Beginner" by michael Dawson.

I have been working through it but am having trouble.
I am trying to make a coin flip program and keep geting a Synax Error
"invalid syntax".

If anyone has a moment could you please look at it and tell me what I am
doing wrong.

thanks for your time and patience.

Chad

# Coin Flip Program
# This program flips a coin 100 times and tells the number of heads and
tails.

Oh, no, it doesn't! Once you fix the few things that stop it from
running at all, it will flip the coin ONCE and tell you the one
then-fixed answer *99* times.

# Chad Everett 2/3/2005


print "\t\t********Coin Flip Game*********\n"
import random

# heads = 1
# tails = 2

tries = random.randrange(2) + 1

Better move the above line _after_ the "while" statement.

count = 1

Try 0; think about it this way: you are counting the number of times
something has happened, and you want to stop after 100 somethings have
happened. At this stage you ain't hatched no chickens
You also need to initialise the 'heads' and 'tails' counters.

while count != 100:

Defensive programming hint #1: while count <= 100, if starting at 1; <
100 if starting from 0

Tip: Python takes the drudgery out of programming. Less typing, less
scope for error. To do something 100 times:

!for count in range(100):
! do_something()

if tries == 1:
heads = 1

I think you meant:
!heads += 1

count += 1

Do this in only one place; it doesn't/shouldn't depend on the coin toss
result.

else tries == 2: # I AM GETTING THE SYNTAX ERROR HERE
tails = 1

and
!tails += 1

count += 1

Others have answered your syntax error question; I'll just round off
with Defensive Programming hint #2:

Get into this habit early:

!if tries == 1:
! blah_blah()
!elif tries == 2:
! yadda_yadda()
!else:
! raise Exception, "Can't happen tries has unexpected value
(%r)" % tries

print "heads: " + heads

Ugh; did you get that out of the book?

Try:
!print "heads:", heads

print "tails: " + tails

raw_input("Press enter to quit")

HTH,
John