LIst in Python Concept Study

In [1]:

l=[]

In [2]:

l=[2,'abc',3.0]
l

Out[2]:

[2, 'abc', 3.0]

In [4]:

l[0]=3

In [5]:

l

Out[5]:

[3, 'abc', 3.0]

In [6]:

l[1]

Out[6]:

'abc'

In [1]:

l2=[3,5,[9,8.0],7]
l2[2]
len(l2)

Out[1]:

4

In [3]:

l2[2][0]

Out[3]:

9

In [9]:

l2[3]

Out[9]:

7

In [5]:

l2[3]

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-5-a11279955f9d> in <module>
----> 1 l2[3][0]

TypeError: 'int' object is not subscriptable

In [19]:

l3=list('i am indian')
l3
l4=str(l3)
len(l3)
print(len(l4))

55

In [12]:

eval('5'+'8')

Out[12]:

58

In [13]:

eval('8+9')

Out[13]:

17

In [14]:

eval('3*10')

Out[14]:

30

In [12]:

v=eval(input('enter value or expression'))
print(v,type(v))

enter value or expression[1,2,3]
[1, 2, 3] <class 'list'>

In [20]:

vow="ae iou"
vowel=list(vow)
print(vow,vowel)

ae iou ['a', 'e', ' ', 'i', 'o', 'u']

In [21]:

s=str(vowel)
print(s)
print(len(s),len(vow),len(vowel))

['a', 'e', ' ', 'i', 'o', 'u']
30 6 6

In [29]:

l1,l2=[1,2,3],[1,2,3]
l1==l2
l1!=l2

Out[29]:

False

In [32]:

Out[32]:

False

In [32]:

l1=l1+l2

In [33]:

l1

Out[33]:

[1, 2, 3, 1, 2, 3]

In [34]:

l1+3

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-34-16f51a34bda7> in <module>
----> 1 l1+3

TypeError: can only concatenate list (not "int") to list

In [35]:

l1*2

Out[35]:

[1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]

In [1]:

eval('5+8')

Out[1]:

13

In [2]:

eval('3*10')

Out[2]:

30

In [3]:

eval('3'*'10')

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-3-9f68aa82b557> in <module>
----> 1 eval('3'*'10')

TypeError: can't multiply sequence by non-int of type 'str'

In [ ]:

v=eval(input('enter value'))
print(v,type(v))

In [ ]:

l1=(4,5,6)
l2=(6,7,8,)

In [ ]:

print(l1>l2)
print(l1<l2)

In [2]:

lst=[10,20,30,40,32,34,40,80,90,23]
se=lst[3:-3]
se

Out[2]:

[40, 32, 34, 40]

In [3]:

se[1]

Out[3]:

32

In [4]:

lst[-12:7]

Out[4]:

[10, 20, 30, 40, 32, 34, 40]

In [5]:

lst[-12:10]

Out[5]:

[10, 20, 30, 40, 32, 34, 40, 80, 90, 23]

In [6]:

lst[-24:24]

Out[6]:

[10, 20, 30, 40, 32, 34, 40, 80, 90, 23]

In [7]:

lst[2:10:3]

Out[7]:

[30, 34, 90]

In [8]:

lst

Out[8]:

[10, 20, 30, 40, 32, 34, 40, 80, 90, 23]

In [9]:

lst[1:3]=[12,34,56]

In [19]:

len(lst)

Out[19]:

12

In [11]:

lst[0:1]=[22,33,44,55,66]

In [14]:

len(lst)

Out[14]:

15

In [13]:

len(lst)

Out[13]:

15

In [17]:

lst[0:5]=[5,5]

In [18]:

lst

Out[18]:

[5, 5, 12, 34, 56, 40, 32, 34, 40, 80, 90, 23]

In [21]:

fst=['i','you','we','they']
fst[0:2]=[45]

In [22]:

fst

Out[22]:

[45, 'we', 'they']

In [23]:

L=[1,2,3]
L[2:]='604'
L

Out[23]:

[1, 2, '6', '0', '4']

In [24]:

L1[2:]=604

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-24-ac453cc80c52> in <module>
----> 1 L1[2:]=604

NameError: name 'L1' is not defined

In [26]:

L1=['a','b','c']
L1[10:20]='xyz'

In [27]:

L1

Out[27]:

['a', 'b', 'c', 'x', 'y', 'z']

In [29]:

L1+='16'

In [31]:

L1*=2

In [32]:

L1

Out[32]:

['a',
 'b',
 'c',
 'x',
 'y',
 'z',
 '1',
 '6',
 'a',
 'b',
 'c',
 'x',
 'y',
 'z',
 '1',
 '6']

In [34]:

L1=['11','22','33','44','55']
L1

Out[34]:

['11', '22', '33', '44', '55']

In [35]:

L1.append(16)

In [36]:

del L1[0]

In [37]:

L1

Out[37]:

['22', '33', '44', '55', 16]

In [38]:

del L1[0:1]

In [39]:

L1

Out[39]:

['33', '44', '55', 16]

In [40]:

del L1[0:2]

In [41]:

L1

Out[41]:

['55', 16]

In [42]:

L1+=[11,12,15,40]

In [1]:

L1

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-1-5163c2dce851> in <module>
----> 1 L1

NameError: name 'L1' is not defined

In [45]:

L1.pop(-1)

Out[45]:

40

In [46]:

L1

Out[46]:

['55', 16, 11, 15]

In [47]:

L1

Out[47]:

['55', 16, 11, 15]

In [48]:

L2

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-48-e2d37c5ab432> in <module>
----> 1 L2

NameError: name 'L2' is not defined

In [49]:

#list copy
c=[1,2,3]
d=c

Out[49]:

[1, 2, 3]

In [55]:

c[1]=9
print(c)
print(d)
#reflect change in both

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-55-d96fed13007c> in <module>
----> 1 c[1]=9
      2 print(c)
      3 print(d)
      4 #reflect change in both

NameError: name 'c' is not defined

In [53]:

#seperate copy list
a=[10,20,30]
b=list(a)
b[1]=40
print(a)
print(b)

[10, 20, 30]
[10, 40, 30]

In [4]:

#copied list reference original List
c=[1,2,3]
d=c
d[1]=9
print(c)
print(d)

[1, 9, 3]
[1, 9, 3]

In [58]:

#index function in List
L1=[13,18,20,18,28,20,35]
print(L1.index(18))
print(L1.index(20))

1
2

In [62]:

#append in List
L2=[]
L2.append(90)
L2.append('ninty')
L3=L2.append('ten')
print(L2)
print(L3)

[90, 'ninty', 'ten']
None

In [2]:

l1=[1,2,3]
l1+=[5,6]

In [3]:

l1

Out[3]:

[1, 2, 3, 5, 6]

In [2]:

t1=[1,2,3]
t2=[4,5,6]
t1.extend(t2)
t1+=t2
t1

Out[2]:

[1, 2, 3, 4, 5, 6, 4, 5, 6]

In [4]:

t1=[3,4,5]
t1.insert(1,9)
t1

Out[4]:

[3, 9, 4, 5]

In [20]:

#index value if more than max index
t1.insert(7,5)
t1

Out[20]:

[5, 5, 4, 4, 3, 3, 2, 5, 5, 2, 1]

In [7]:

#index value if less than min index
t1.insert(-8,88)
t1

Out[7]:

[88, 3, 9, 4, 5, 5]

In [10]:

#it will remove all element from list
t1.clear()
t1

Out[10]:

[]

In [23]:

#count number of item freuency in list
t1=[1,2,2,3,3,3,4,4,5,5]
t1.count(3)

Out[23]:

3

In [12]:

t1.count(2)

Out[12]:

2

In [13]:

t1.count(3)

Out[13]:

2

In [14]:

t1.reverse()
t1

Out[14]:

[5, 5, 4, 4, 3, 3, 2, 2, 1]

In [15]:

t1.sort()

In [16]:

t1

Out[16]:

[1, 2, 2, 3, 3, 4, 4, 5, 5]

In [17]:

t1.sort(reverse=True)

In [18]:

t1

Out[18]:

[5, 5, 4, 4, 3, 3, 2, 2, 1]

In [21]:

t1=[1,2,3]
t1.insert(7,5)
t1

Out[21]:

[1, 2, 3, 5]

In [24]:

l=['abc','zxzx','nnnn','aaa']
l.sort()
l

Out[24]:

['aaa', 'abc', 'nnnn', 'zxzx']

In [27]:

l.sort(reverse=False)
l

Out[27]:

['aaa', 'abc', 'nnnn', 'zxzx']

In [28]:

l=['A','B','aaa']
l.sort()
l

Out[28]:

['A', 'B', 'aaa']

In [29]:

ord(1)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-29-77e5aeef42fb> in <module>
----> 1 ord(1)

TypeError: ord() expected string of length 1, but int found

In [30]:

chr(1)

Out[30]:

'\x01'

In [31]:

chr(97)

Out[31]:

'a'

In [32]:

ord('A')

Out[32]:

65

In [33]:

ord('1')

Out[33]:

49

In [34]:

ord('a')

Out[34]:

97

In [ ]: