01-basicdata.rst

examples

::

>>> 1 + 1
2

>>> 2 * 3
6

>>> 2.5 * 3
7.5

>>> type(1)
<type 'int'>

>>> type(7.5)
<type 'float'>

>>> a = 13

>>> type(a)
<type 'int'>

>>> 4.0/3
1.3333333333333333

>>> a = 4.0/3

>>> a
1.3333333333333333

>>> type(a)
<type 'float'>

tipul este asociat valorii, nu variabilei

::

>>> type("Hello")
<type 'str'>

>>> "Hello" + "world!"
'Helloworld!'

>>> "Your lucky number is %d" % 13
'Your lucky number is 13'

>>> "Your other number is %d" % a
'Your other number is 1'

>>> "Your other number is %f" % a
'Your other number is 1.333333'

>>> "Your other number is %.2f" % a
'Your other number is 1.33'

>>> msg = "Your other number is %.2f" % a

>>> len(msg)
25

>>> msg[0]
'Y'

>>> msg[1]
'o'

>>> msg[-1]
'3'

>>> msg[12:17]
'umber'

string-urile au metode

::

>>> msg.lower()
'your other number is 1.33'

>>> msg.find("number")
11

>>> msg.split(" ")
['Your', 'other', 'number', 'is', '1.33']

am primit o listă! putem defini propriile liste

::

>>> l = ['ana', 'are', 'mere']

>>> l
['ana', 'are', 'mere']

>>> type(l)
<type 'list'>

>>> l[0]
'ana'

>>> type(l[0])
<type 'str'>

>>> l.pop()
'mere'

>>> l.append("cartofi")

>>> l
['ana', 'are', 'cartofi']

>>> l.extend(["si", 3, "mere"])

>>> l
['ana', 'are', 'cartofi', 'si', 3, 'mere']

listele primesc conținut de orice type

::

>>> type(l[4])
<type 'int'>

>>> ' '.join(l)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: sequence item 4: expected string, int found

type checking la runtime

::

>>> l.pop(4)
3

>>> ' '.join(l)
'ana are cartofi si mere'

remember, string-urile au metode

::

>>> ship = {'name': "Enterprise", 'enemies': ['ferengi', 'cardassian']}

>>> len(ship)
2

>>> ship.keys()
['name', 'enemies']

>>> type(ship['name'])
<type 'str'>

>>> type(ship['enemies'])
<type 'list'>

primește orice fel de valori

::

>>> ship['enemies'].append('borg')

>>> ship
{'name': 'Enterprise', 'enemies': ['ferengi', 'cardassian', 'borg']}

>>> ship[1] = 'Riker'

>>> ship
{1: 'Riker', 'name': 'Enterprise', 'enemies': ['ferengi', 'cardassian', 'borg']}

primește integer la chei (în general non-mutable values)

::

>>> ship[l] = "hello"
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'

>>> del ship['enemies']

>>> ship
{1: 'Riker', 'name': 'Enterprise'}

if/else, for

::

>>> if 2 < 3:
...     print "doi e mai mic decat trei!"

>>> if False:
...     print "WTF?!"
... else:
...     print "totul e ok"

>>> for c in range(30):
...   if c % 2 == 0:
...     print "Numar par:", c

>>> l = [c**2 for c in range(20)]
>>> for c in l:
...     print 'numarul este', c