Coursera课程Python for everyone：chapter3

Chapter 3

10 试题

1. 

What do we do to a Python statement that is immediately after an if statement to indicate that the statement is to be executed only when the if statement is true?

Indent the line below the if statement

Begin the statement with a curly brace {

Start the statement with a "#" character

Underline all of the conditional code

2. 

Which of these operators is not a comparison / logical operator?

<=

>=

==

!=

=

3. 

What is true about the following code segment:

if  x == 5 :    print 'Is 5'    print 'Is Still 5'    print 'Third 5'

Depending on the value of x, either all three of the print statements will execute or none of the statements will execute

The string 'Is 5' will always print out regardless of the value for x.

The string 'Is 5' will never print out regardless of the value for x.

Only two of the three print statements will print out if the value of x is less than zero.

4. 

When you have multiple lines in an if block, how do you indicate the end of the if block?

You use a curly brace { after the last line of the if block

You de-indent the next line past the if block to the same level of indent as the original ifstatement

You capitalize the first letter of the line following the end of the if block

You omit the semicolon ; on the last line of the if block

5. 

You look at the following text:

if x == 6 :    print 'Is 6'    print 'Is Still 6'    print 'Third 6'

It looks perfect but Python is giving you an 'Indentation Error' on the second print statement. What is the most likely reason?

Python has reached its limit on the largest Python program that can be run

In order to make humans feel inadequate, Python randomly emits 'Indentation Errors' on perfectly good code - after about an hour the error will just go away without any changes to your program

Python thinks 'Still' is a mis-spelled word in the string

You have mixed tabs and spaces in the file

6. 

What is the Python reserved word that we use in two-way if tests to indicate the block of code that is to be executed if the logical test is false?

otherwise

toggle

else

iterate

7. 

What will the following code print out?

x = 0if x < 2 :    print 'Small'elif x < 10 :    print 'Medium'else :    print 'LARGE'print 'All done'

All done

Small

All done

LARGE

All done

Small

Medium

LARGE

All done

8. 

For the following code,

if x < 2 :    print 'Below 2'elif x >= 2 :     print 'Two or more'else :    print 'Something else'

What value of 'x' will cause 'Something else' to print out?

x = -2.0

x = -2

This code will never print 'Something else' regardless of the value for 'x'

x = 2.0

9. 

In the following code (numbers added) - which will be the last line to execute successfully?

(1)   astr = 'Hello Bob'(2)   istr = int(astr)(3)   print 'First', istr(4)   astr = '123'(5)   istr = int(astr)(6)   print 'Second', istr

2

5

1

6

10. 

For the following code:

astr = 'Hello Bob'istr = 0try:    istr = int(astr)except:    istr = -1

What will the value be for istr after this code executes?

It will be the 'Not a number' value (i.e. NaN)

false

-1

It will be a random number depending on the operating system the program runs on