Exercise 22 - Python Words & Symbols

Question 0

print ‘string’

Answer 0

Prints a string

Question 1

print “string”

Answer 1

Prints a string

Question 2

#

Answer 2

(Octothorpe) - starts a comment

Question 3

+

Answer 3

(Plus) - adds

Question 4

-

Answer 4

(Minus) - subtracts

Question 5

/

Answer 5

(Slash) - divides

Question 6

*

Answer 6

(Asterisk) - multiplies

Question 7

%

Answer 7

(Percent sign) - mod or modulus function

Question 8

<

Answer 8

Less than - compares two values or strings, returns True or False

Question 9

>

Answer 9

Greater than - compares two values or strings, returns True or False

Question 10

<=

Answer 10

Less than equal - compares two values or strings, returns True or False

Question 11

> =

Answer 11

Greater than equal - compares two values or strings, returns True or False

Question 12

=

Answer 12

Assigns a value or string to a variable, I.e., var = “ text” or var = 3

Question 13

,

Answer 13

Comma, separates lists of things

Question 14

%s

Answer 14

Format character, string

Question 15

%d

Answer 15

Format character, number

Question 16

%r

Answer 16

Format character, returns input, I.e., raw contents of the variable = ‘representation’

Question 17

% var

Answer 17

Places var in formatter location

Question 18

% (var1, var2, var3)

Answer 18

Places vars in multiple formatter locations

Question 19

3.0, for example

Answer 19

Appending .0 to the 3 results in floating point math operations

Question 20

round()

Answer 20

Rounds a floating point number

Question 21

False

Answer 21

Logical false

Question 22

True

Answer 22

Logical true

Question 23

• used with a string

Answer 23

Repeats a string char, I.e., print “.” * 10 results in ……….

Question 24

+ used with strings

Answer 24

Concatenates the strings in the print function

Question 25

, used with print

Answer 25

Removes the line feed at the end of print, I.e., 
print "Mary", 
print "lamb"
Results in:
Mary lamb

Question 26

\

Answer 26

(Backslash) - escape character

Question 27

print “"”…”””

print ‘'’…’’’

Answer 27

Triple quotes allow printing of lines as typed

Question 28

raw_input( )

Answer 28

Prompts user for a string or a value, outputs a string

Question 29

int(raw_input( ))

Answer 29

Converts string to a number

Question 30

Input( )

Answer 30

Converts entry as if it is python code; security issues, don’t use

Question 31

raw_input(“string”)

Answer 31

Prompts for input by printing “string”

Question 32

pydoc

Answer 32

Terminal command that prints python documentation, I.e., pydoc raw_input() prints doc for raw_input()

Question 33

From sys import argv

Answer 33

Imports function argv from sys (sys is a package)

Question 34

argv

Answer 34

Packs arguments given to a program; first one is the function (script) name

Question 35

module

Answer 35

Another name for a function or feature

Question 36

Prompt

Answer 36

”> “ is one, I.e., raw_input(“> “)

Question 37

var = raw_input(“> “)

Answer 37

Passes user input to var

Question 38

var = open(filename)

Answer 38

Opens the file “filename” and passes file object to var

Question 39

var.read()

Answer 39

Reads the contents of var if var is file info, e.g.:
var = open(filename)
print var.read()
Prints contents of filename as contained in var

Question 40

close()

Answer 40

closes the file, e.g.:
    var = open(filename)
    ...
    ....
    var.close()

Question 41

.close()

Answer 41

Close the file

Question 42

.read()

Answer 42

Read the file

Question 43

.readline()

Answer 43

Read one line of a text file

Question 44

.truncate()

Answer 44

Empty the file

Question 45

.write(stuff)

Answer 45

Writes stuff to the file

Question 46

Open(filename, ‘w’)

Answer 46

Opens filename and allows writing to the file. Can use:
‘w’ write, ‘r’ read, ‘a’ append
Default is read, so ‘r’ can be omitted

Question 47

from os.path import exists

Answer 47

Imports exists module

Question 48

exists(filename)

Answer 48

Returns True if filename exists, else False

This is the exists module

Question 49

cat

Answer 49

Concatenation, Linux command

cat filename prints the contents of filename

Question 50

len(string)

Answer 50

Outputs the character count of a string as a number

Question 51

def

Answer 51

defines a function
def print_two(*args):
      arg1, arg2 = args
      print "arg1: %r, arg2: %r" % (arg1, arg2)

Question 52

.seek(0)

Answer 52

Rewinds a .read() of a file

Question 53

+= n

Answer 53

Increments a variable by n

var += 2 is equivalent to var = var + 2

Question 54

return

Answer 54

Returns a value from a function
def add(a, b)
      return a + b
Executing var = add(3, 4) places 7 in var