Python3

Front 1

How to get input from the keyboard to one program?

Back 1

input( )

Example:
>>> name = input('what is your name? ')

Front 2

Using function input to get numbers, what is the type of them once receive?

Back 2

They turn to string.

Front 3

What is the main advantage of triple quotes (''')?

Back 3

Allows to write a string in multiple lines.

Front 4

How to see the functions in a imported module?

Back 4

import math
dir(math) # will show all the functions in this module.

Front 5

What is the error in code below and what is the fix for it?
>>> i = 0
>>> s = 'xyz'
>>> while not (s[i] in 'aeiouAEIOU'):
print(s[i])
i = i + 1

Back 5

In the code above, the error occurs when s is indexed at i and i is outside of the range of valid indices. To prevent this error, add an additional condition is added to ensure that i is within the range of valid indices for s:

>>> i = 0
>>> s = 'xyz'
>>> while i < len(s) and not (s[i] in 'aeiouAEIOU'):
print(s[i])
i = i + 1

Front 6

How to more generally refers to the end of the string s?

Back 6

Use the function len(s) or let it empty [m:].Example:
can be represented using its length:
s = 'Program'
>>> s[:len(s)]
'Program' #or
>>> s[2:]
'ogram'

Front 7

Given a string s, why the statment below is wrong?

>>> s[6] = 'd'
Traceback (most recent call last):
File <"pyshell#19", line 1, in
s[6] = 'd'
TypeError: 'str' object does not support item assignment

Back 7

The slicing and indexing operations do not modify the string that they act on, so the string that s refers to is unchanged by the operations above. In fact, we cannot change a string. Operations like the previous result in errors. To change a string s use:
>>> s = 'Learn to Program'
>>> s = s[:5] + 'ed' + s[5:]
>>> 'Learned to Program'

Front 8

How to convert a string s uppercase?

Back 8

Use the method upper()
S.upper() -> string
Return a copy of the string S converted to uppercase.
>>> s
'Learned to Program'
>>> s.upper()
'LEARNED TO PROGRAM'

Front 9

How to convert a uppercase string s to lowercase?

Back 9

Use method s.lower()
>>> s = 'LEARNED TO PROGRAM'
>>> s.lower()
'learned to program'

Front 10

How to count the occurrence of substring sub in a string s?

Back 10

Use method s.count()
S.count(sub[, start[, end]]) -> int
Return the number of non-overlapping occurrences of substring sub in string S[start:end]. Optional arguments start and end are interpreted as in slice notation.

Front 11

How to locate a substring inside a string?

Back 11

Use method s.find()

S.find(sub [,start [,end]]) -> int

Return the lowest index in S where substring sub is found, such that sub is contained within s[start:end]. Optional arguments start and end are interpreted as in slice notation.

Return -1 on failure.

Front 12

How is it called the special no-value value in python?

Back 12

None

Front 13

Is logical operators case sensitive?

Back 13

Yes. True / False are not the same as true and false

Front 14

What is the operand of floor division?

Back 14

//

>>>3//2
>>> 1

Front 15

What is the operand of modulo operation?

Back 15

%
>>> 11 % 4
>>> 3

Front 16

How to revert a string s using slicing?

Back 16

s[ : : -1]

Front 17

How to slice a string with a periodic pace?

Back 17

Use a third parameter among the brackets. Example:
'MNKMDLVADVAEKTDLS'[16:0:-4]
'SKDD'
# In this example it make the reverse slicing.

Front 18

what the function isinstance(...) does?

Back 18

isinstance(object, class-or-type-or-tuple) -> bool

Return whether an object is an instance of a class or of a subclass thereof. With a type as second argument, return whether that is the object's type. Ex:
>>> isinstance('hello', str)
True
>>> isinstance(7, int)
True
>>> isinstance(1.5, float)
True

Front 19

What the call: string1.count(string2[, start[, end]]) returns?

Back 19

Returns the number of times string2 appears in string1. If start is specified, starts
counting at that position in string1; if end is also specified, stops counting before
that position in string1.

Front 20

What is return from the call:string1.find(string2[, start[, end]])

Back 20

Returns the position of the first occurrence of string2 in string1; −1 means
string2 was not found in string1. If start is specified, starts searching at that
position in string1; if end is also specified, stops searching before that position in
string1.

Front 21

What is return from the call: string1.startswith(string2[, start[, end]])?

Back 21

Returns True or False according to whether string2 starts with string1. If start is
specified, uses that as the position at which to start the comparison; if end is also
specified, stops searching before that position in string1.

Front 22

What is return from the call: string1.strip([string2])?

Back 22

Returns a string with all characters in string2 removed from its beginning and end;
if string2 is not specified, all whitespace is removed.

Front 23

What is return from the call: string1.lstrip([string2]) ?

Back 23

Returns a string with all characters in string2 removed from its beginning; if
string2 is not specified, all whitespace is removed.

Front 24

What is returned from the call: string1.rstrip([string2])?

Back 24

Returns a string with all characters in string2 removed from its end; if string2 is
not specified, all whitespace is removed.

Front 25

If you get errors about ASCII encodings, what can be done?

Back 25

then put this at the top of your python scripts:

# -*- coding: utf-8 -*-