Chapter 8 Lists

CHAPTER 8

Lists

Keynote

8.1 Lists

Container timi cu data item tam nawn a khongtu (a chungah a chiahtu) a si. "Collection" asiloah "Compound data type" tiah auh a si.

Python nih a tanglei Container phun hna hi a ngei:

• Lists
• Tuples
• Sets
• Dictionaries

List cu program a kal lioah a ṭhang (grow) kho i a zor (shrink) kho. Cucaah Dynamic Array tiah auh a si. Hi a sining ruangah hin, data zeizat dah an si ti hngalh lomi (variable length data) tawlrel nak ah hman a si.

List cu [ ] (Square brackets) chungah element pawl comma , in ṭhen in ṭial a si.

Defining lists

# Nambat (Integer) list
num = [10, 25, 30, 40, 100] 

# Cafang (String) list
names = ['Shine', 'Anna', 'Rosanna', 'Superior']

List chungah data phun aa lo lomi (dissimilar types) zong chiah khawh a si. Nain a tlangpi in cun data phun aa lomi lawng chiah tawn a si.

List containing dissimilar types

animal = ['Zebra', 155.55, 110] 

List chungah item pawl hi an i nawn (repeat) kho, a sullam cu list nih duplicate items a ngei kho.

String ah kan hman bantuk in, * hman in element kan duh zat kan karh (repeat) khawh. List a lawng (Empty list) zong tuah khawh a si.

Repeating list elements

ages = [25, 26, 25, 27, 26] # Duplicate (aa nawnmi) a ngah 
num = [10] * 5 # [10, 10, 10, 10, 10] tiah a chiah lai
lst = [ ] # List a lawng (Empty list), a hman

8.2 Accessing List Elements

List min hman in list chung ummi dihlak chuah (print) khawh a si.

Printing list

l = ['Able', 'was', 'I', 'ere', 'I', 'saw', 'elbA'] 
print(l)

String bantuk in, list chung i element pakhat cio kha indices (index pawl) hman in lak khawh an si. Cucaah Sequence types tiah auh an si. Index value cu 0 in a thawk.

# animals i index 1 le ages i index 3 lak
print(animals[1], ages[3]) 

String bantuk in, List zong kan tan (slice) khawh.

Slicing lists

# Index 1 in thawk, Index 3 hlan ah ngol (Index 3 a tel lo)
print(animals[1:3]) 

# Index 3 in thawk, a dongh tiang lak
print(ages[3:]) 

8.3 List Chung I Kalnak (Looping in Lists)

List chung i item pakhat cio kha tawlrel (process) kan duh ahcun, list chungah khan a nung in kan kal (iterate) khawh a hau. Hihi while loop asiloah for loop hman in tuah khawh a si.

Looping through a list

animals = ['Zebra', 'Tiger', 'Lion', 'Jackal', 'Kangaroo'] 

# while loop hman in 
i = 0 
while i < len(animals) : 
    print(animals[i]) 
    i += 1 

# hman a fawi deuhmi for loop hman in 
for a in animals : 
    print(a)

for loop hman in list chung kan kal lioah, element pakhat cio i a index (a umnak nambat) kha hngalh chih kan duh ahcun, built-in enumerate( ) function kha kan hman khawh.

Iterating through a list using enumerate()

animals = ['Zebra', 'Tiger', 'Lion', 'Jackal', 'Kangaroo'] 

# enumerate nih index (nambat) le a value (sata) kha a peh hna
# index = 0, 1, 2...
# a = Zebra, Tiger...
for index, a in enumerate(animals) : 
    print(index, a)

8.4 Basic List Operations (List Tuah Khawhmi Thil Hna)

Mutability (Thlen Khawh Sining) - String he i lo loin, List hna cu mutable (thlen khawh) an si. Cucaah list hna cu a tanglei bantuk in thlen asiloah update khawh an si:

Mutating lists

animals = ['Zebra', 'Tiger', 'Lion', 'Jackal', 'Kangaroo'] 
ages = [25, 26, 25, 27, 26, 28, 25] 

# 1. Element pakhat thlen (Update single item)
animals[2] ='Rhinoceros' # Index 2 (Lion) kha 'Rhinoceros' ah a thleng
ages[5] = 31             # Index 5 kha 31 ah a thleng

# 2. Slice hman in element tam nawn thlen
# Index 2 in 4 tiang (2, 3, 4) kha [24, 25, 32] in a thleng
ages[2:5] = [24, 25, 32] 

# 3. Slice hman in element hrawh (Delete)
# Index 2 in 4 tiang kha a hlonh/hrawh (Empty list in thlen)
ages[2:5] = [ ]

Concatenation (Peh/Fonk) - List pakhat cu list dang a donghnak ah a tanglei bantuk in kan peh (concatenate) khawh:

Concatenating lists

lst = [12, 15, 13, 23, 22, 16, 17] 

# List hlun (+ sign) List thar
lst = lst + [33, 44, 55] 

print(lst) 
# A chuahmi: [12, 15, 13, 23, 22, 16, 17, 33, 44, 55]

Merging (Fonh) - List pahnih kha kan fonh (merge) hna in list thar kan ser khawh.

Merging lists

s = [10, 20, 30] 
t = [100, 200, 300] 

# s le t kan fonh i z ah kan chiah
z = s + t 

print(z) # [10, 20, 30, 100, 200, 300] tiah a chuah lai

Conversion (Thlen) - String, tuple, asiloah set hna cu list( ) function hman in List ah kan thlen khawh hna.

Converting string to list

lst = list('Africa') 
# String kha list ['A', 'f', 'r', 'i', 'c', 'a'] ah a thlen
print(lst)

Aliasing - List pakhat kha list dang ah kan chiah (assign) tikah, an pahnih in list khat kha an sawh (refer). Pakhat kan thlen ahcun a dang pakhat zong kha a thleng ve. Hi thil hi Shallow copy asiloah Aliasing tiah auh a si.

Aliasing a list

lst1 = [10, 20, 30, 40, 50] 
lst2 = lst1 # List a copy lo. lst2 nih lst1 he list khat a sawh. 

print(lst1) # [10, 20, 30, 40, 50] tiah a chuah 
print(lst2) # [10, 20, 30, 40, 50] tiah a chuah 

lst1[0] = 100 # lst1 kan thlen
print(lst1[0], lst2[0]) # lst2 zong a thleng ve. 100 100 tiah a chuah 

Cloning - Mah hi cu list pakhat i a chung thil pawl kha list dang ah copy tuah a si. Copy kan tuah hnu ahcun, an pahnih in list dang dang an sawh (refer), nain a chung value tu cu an i khat. List pakhat kan thlen ahcun, a dang pakhat kha a thleng ve lo. Hi thil hi Deep copy tiah auh a si.

Cloning a list

lst1 = [10, 20, 30, 40, 50] 
lst2 = [ ] # list a lawng
lst2 = lst2 + lst1 # lst1 le lst2 cu list dang dang an si cang

print(lst1) # [10, 20, 30, 40, 50] tiah a chuah 
print(lst2) # [10, 20, 30, 40, 50] tiah a chuah 

lst1[0] = 100 # lst1 lawng a thleng
print(lst1[0], lst2[0]) # 100, 10 tiah a chuah (lst2 a thleng lo)

Kawl (Searching) - List chungah element pakhat kha in membership operator hman in kan kawl khawh. A tanglei bantuk in:

Searching in a list

lst = ['a', 'e', 'i', 'o', 'u'] 

# 'a' cu list chungah a um caah True a chuah (return)
res = 'a' in lst 

# 'z' cu list chungah a um LO caah True a chuah (return)
res = 'z' not in lst

Identity - Variable pahnih nih list khat kha an sawh (refer) maw sawh lo ti kha is identity operator hman in chek khawh a si. A tanglei bantuk in:

Checking identity of lists

lst1 = [10, 20, 30, 40, 50] 
lst2 = [10, 20, 30, 40, 50] 
lst3 = lst1 

# lst1 le lst2 cu value aa lo nain, memory ah hmun dang an si
print(lst1 is lst2) # False tiah a chuah 

# lst3 cu lst1 nih a sawhmi kha a sawh ve (Aliasing)
print(lst1 is lst3) # True tiah a chuah 

print(lst1 is not lst2) # True tiah a chuah

Note: int asiloah str tibantuk basic types hna sinah cun a sining a dang deuh, mah hi cinchiah a hau:

Checking identity of basic types

num1 = 10 
num2 = 10 
s1 = 'Hi' 
s2 = 'Hi' 

# Nambat (int) le String (str) ah cun, value aa lo ahcun 
# object khat (memory hmun khat) an sawh tawn.
print( num1 is num2) # True tiah a chuah 
print( s1 is s2) # True tiah a chuah

Comparison (Tahchunh) - List pahnih chung thil pawl kha tahchunh (compare) khawh a si. Tahchunhnak cu item pakhat hnu pakhat (item by item) in tuah a si i, an i loh lonak (mismatch) a um hlan lo tuah a si.

A tanglei code ah hin, 3 le 5 an i tahchunh tikah a cu b nakin a niam deuh (less than) tiah bia a khiah lai.

Comparing lists

a = [1, 2, 3, 4] 
b = [1, 2, 5] 
print(a < b) # True tiah a chuah

Emptiness (A Lawng Sining) - List pakhat a lawng (empty) maw a lawng lo ti cu not operator hman in kan check khawh.

Checking emptiness of a list

lst = [ ] 

# List a lawngmi cu Python ah 'False' a si.
# Cucaah 'not lst' cu 'True' a si lai.
if not lst : 
    print('Empty list') 

Alternately (Lam dang in) - List kha boolean ah thlen in a phi (result) kan check khawh.

Checking emptiness of a list

lst = [ ] 
print(bool(lst)) # False tiah a chuah 

Note: A tanglei value pawl hi False an si tiah ruah an si:

Checking emptiness of a list

None 

# Zero he aa lukmi nambat pawl: 
0, 0.0, 0j 

# String, List le Tuple a lawngmi (Empty): 
'', "", [], () 

# Set le Dictionary a lawngmi (Empty): 
{}

8.5 Using Built-in Functions on Lists (List Cungah Built-in Function Pawl Hman)

List he hman khawhmi built-in function tam pi a um.

Using built-in functions on lists

len(lst)      # List chung i item zat a chuah
max(lst)      # List chung i a ngan bik (maximum) element a chuah
min(lst)      # List chung i a niam bik (minimum) element a chuah
sum(lst)      # List chung element dihlak a fonh (sum) a chuah
any(lst)      # List chung i element *pakhat khat* True a si ahcun True a chuah
all(lst)      # List chung i element *dihlak* True an si ahcun True a chuah
del( )        # Element, slice, asiloah list dihlak hrawh nak
sorted(lst)   # List a tlar (sort) ciami a chuah, a hrampi list a thleng lo
reversed(lst) # List let (reverse) nak ah hman a si

A donghnak pathum (3) dah ti lo cu, function dang pawl hi cu anmah tein an ifiang ko. sorted( ) le reversed( ) cu hika hnu section hnihnak ah kan chim te lai. del( ) function hman ning cu a tanglei bantuk in a si:

Using del( ) function

lst = [10, 20, 30, 40, 50] 

del lst[3]    # List chung i item 3-nak hlonh/hrawh 
del lst[2:5]  # List chung i item 2 in 4 tiang hlonh/hrawh 
del lst[:]    # List dihlak hlonh/hrawh 
lst = [ ]     # List dihlak hlonh nak lam dang

Variable tam nawn nih list khat an sawh (refer) ahcun, pakhat hlonh (delete) asiloah thlen nih a dang pawl kha a hrawh ve hna lo.

Using del( ) function

lst1 = [10, 20, 30, 40, 50] 
lst3 = lst2 = lst1 # An dihlak in list khat an sawh 

lst1 = [ ] # lst1 cu list thar (a lawngmi) a sawh cang; 
           # lst2 le lst3 cu list hlun a sawh rih 

print(lst2) # [10, 20, 30, 40, 50] tiah a chuah 
print(lst3) # [10, 20, 30, 40, 50] tiah a chuah

Variable tam nawn nih list khat an sawh (refer) i, kha list chung thil vialte kha hrawh (delete) kan duh ahcun, a tanglei bantuk hin kan tuah khawh:

Using del( ) function

# List chung item vialte hrawh (slice hman in)
lst2[:] = [ ] 

# List khat kha an sawh (refer) caah, an dihlak in a lawng cang lai
print(lst2) # [ ] tiah a chuah
print(lst3) # [ ] tiah a chuah 

8.6 List Methods (List Method Pawl)

List paohpaoh hi list type object an si. A chung i method pawl kha lst.method( ) tiin kan hmang khawh hna. A tanglei hi hman tam bikmi method pawl an si:

Using list methods

lst = [12, 15, 13, 23, 22, 16, 17] # list sernak

lst.append(22)   # A donghnak ah item thar (22) telh nak
lst.remove(13)   # List chungin item 13 hrawh nak
lst.remove(30)   # ValueError a chuah lai, 30 cu list chungah a um lo
lst.pop( )       # A dongh bik i a ummi item hrawh nak
lst.pop(3)       # Index 3-nak i a ummi item hrawh nak
lst.insert(3,21) # Index 3-nak hmun ah 21 va thun (insert) nak
lst.count(23)    # List chungah 23 hi voi zeizat dah a um ti relnak
idx = lst.index(22) # 22 a umnak index nambat kawlnak
idx = lst.index(50) # ValueError a chuah lai, 50 cu list chungah a um lo

8.7 Sorting and Reversing (Tlar le Let)

List chung i element pawl a let (reverse) ning le a tlar (sort) ning method hmannak cu a tanglei bantuk hi a si:

Using list methods

lst = [10, 2, 0, 50, 4] 

# List chung thil pawl a hram thawk in a let (reverse) nak
lst.reverse( ) 
print(lst) # [4, 50, 0, 2, 10] tiah a chuah lai

# List chung thil pawl a niam in a sang (ascending) ah tlar nak
lst.sort( ) 
print(lst) # [0, 2, 4, 10, 50] tiah a chuah lai

# A sang in a niam (descending) ah tlar nak
lst.sort(reverse = True) 
print(lst) # [50, 10, 4, 2, 0] tiah a chuah lai

• Cinchiah ding: reverse( ) le sort( ) method hna nih hin list thar an chuah (return) lo. An pahnih in a hrampi list kha a hmun (in place) ah an thlen (manipulate) colh.

List let (reverse) ning le tlar (sort) ning built-in function hman ning cu a tanglei bantuk hi a si:

Using built-in functions

lst = [10, 2, 0, 50, 4] 

# List a tlar (sort) ciami a chuah, nain a hrampi list 'lst' a thleng lo
print(sorted(lst)) # [0, 2, 4, 10, 50] tiah a chuah lai

# A sang in a niam ah tlar nak (Descending order)
print(sorted(lst, reverse = True)) # [50, 10, 4, 2, 0] tiah a chuah lai

# reversed() nih iterator a chuah caah list() in kan thlen a hau
print(list(reversed(lst))) # [4, 50, 0, 2, 10] tiah a chuah lai

- Cinchiah ding: sorted( ) function nih cun list thar (a tlar ciami) kha a chuah (return) i, a hrampi list (original list) cu a thleng lo. Cun, reversed( ) function nih hin list_reverseiterator object a chuah tawn caah, a let (reversed) ciami list kan hmuh khawh nakhnga list( ) function hman in thlen a hau.

List let (reversal) cu a tanglei bantuk in slicing hman zongin a tuah khawh:

Using slicing operation

lst = [10, 2, 0, 50, 4] 

# List a hram thawk in a dongh tiang a let (reverse) in laknak
print(lst[::-1]) # [4, 50, 0, 2, 10] tiah a chuah lai

8.8 List Varieties (List Phunphun)

List chungah list dang a ummi (nested lists) zong kan ser khawh.

a = [1, 3, 5, 7, 9] 
b = [2, 4, 6, 8, 10] 

# List 'a' le 'b' kha list 'c' chungah kan thun hna
c = [a, b] 

# Index hnih hman a hau (Row le Column bantuk in)
# c[0][0] -> List 0-nak i element 0-nak (1)
# c[1][2] -> List 1-nak i element 2-nak (6)
print(c[0][0], c[1][2]) # 1 6 tiah a chuah lai

List pakhat cu list dang chungah kan thun (embed) khawh.

x = [1, 2, 3, 4] 

# List 'x' kha list 'y' chungah a ummi item pakhat bantuk in kan thun
y = [10, 20, x, 30] 

print(y) 
# A chuahmi (output): [10, 20, [1, 2, 3, 4], 30]

String asiloah list kha list dang chungah * operator hman in a chung thil hna kha kan unpack (phoih/thep) khawh hna.

s = 'Hello' 
l = [*s] 
# String kha a cafang pakhat cio in a phoih (unpack) hna
print(l) # ['H', 'e', 'l', 'l', 'o'] tiah a chuah lai

x = [1, 2, 3, 4] 
# List 'x' chung i a ummi nambat hna kha a hmun cio ah a phoih hna
y = [10, 20, *x, 30] 
print(y) # [10, 20, 1, 2, 3, 4, 30] tiah a chuah lai

8.9 Stack Data Structure

Data structure timi cu memory chungah sining pakhat (arrangement) in hnaṭuan khawh nakhnga thil tuahmi a si. Stack, queue, tree, graph le map hna hi minthang bikmi data structure an si.

Stack cu Last In First Out (LIFO) list a si. Mah cu a dongh bikah kan telhmi (last element) kha a hmasa bikah kan hlonhmi (first element) a si tinak a si.

• Stack chungah element thar telh kha Push operation tiah auh a si.
• Stack chungin element hlonh/chuah kha Pop operation tiah auh a si.

Hi hnaṭuannak pahnih hi list i a donghnak (rear end) ah tuah tawn a si. append() le pop() method hna hmang in Stack cu a tanglei bantuk in tuah khawh a si.

---

8.10 Queue Data Structure

Queue cu First In First Out (FIFO) list a si. Mah cu a hmasa bikah kan telhmi kha a hmasa bikah kan hlonhmi a si tinak a si (Minung tlar (line) kan i tlar bantuk in).

Queue caah hin List hna hi hman an tlak (efficient) tuk lo. A chanchu, List i a hram (beginning) in thil hlonh tikah, a dang element vialte kha hmun khat cio va ṭuan (shifting) a herh caah a tlawm (slow).

Cucaah, thil telh le hlonh a ran nakhnga, collections module chung i deque class kha hman deuh a si.

Deque timi cu Double Ended Queue tinak a si. Deque ah cun a hram le a dongh (both ends) hmun hnih in thil telh le hlonh khawh a si.

Problems

Problem 8.1

List Operation Tuah Ning Tahchunhnak

A tanglei hnaṭuannak (operations) hna hi min tlar (list of names) cungah tuah hna:

• Min 5 unnak list ser - 'Anil', 'Amol', 'Aditya', 'Avi', 'Alka'
• 'Anuj' kha 'Aditya' hlan ah thun (Insert)
• 'Zulu' kha a donghnak ah telh (Append)
• 'Avi' kha list chungin hlonh (Delete)
• 'Anil' hmun ah 'AnilKumar' in thlen (Replace)
• Min vialte kha a tlar (Sort) in chiah
• A tlar ciami kha a let (Reverse) in print tuah

Program

# 1. Min 5 unnak list sernak
names = ['Anil', 'Amol', 'Aditya', 'Avi', 'Alka'] 
print(names) 

# 2. 'Anuj' kha 'Aditya' hlan (index 2) ah thun (insert) nak
names.insert(2, 'Anuj') 
print(names) 

# 3. 'Zulu' kha a donghnak ah telh (append) nak
names.append('Zulu') 
print(names) 

# 4. 'Avi' kha list chungin hlonh (delete) nak
names.remove('Avi') 
print(names) 

# 5. 'Anil' hmun ah 'AnilKumar' in thlen (replace) nak
i = names.index('Anil') # 'Anil' a umnak index kawl hmasa a hau
names[i] = 'AnilKumar' 
print(names) 

# 6. Min vialte kha a tlar (sort) in chiah nak
names.sort( ) 
print(names) 

# 7. A tlar ciami kha a let (reverse) in print tuah nak
names.reverse( ) 
print(names)

Output

['Anil', 'Amol', 'Aditya', 'Avi', 'Alka'] 
['Anil', 'Amol', 'Anuj', 'Aditya', 'Avi', 'Alka'] 
['Anil', 'Amol', 'Anuj', 'Aditya', 'Avi', 'Alka', 'Zulu'] 
['Anil', 'Amol', 'Anuj', 'Aditya', 'Alka', 'Zulu'] 
['AnilKumar', 'Amol', 'Anuj', 'Aditya', 'Alka', 'Zulu'] 
['Aditya', 'Alka', 'Amol', 'AnilKumar', 'Anuj', 'Zulu'] 
['Zulu', 'Anuj', 'AnilKumar', 'Amol', 'Alka', 'Aditya']

Problem 8.2

List Nambat Hna Hman Ning Tahchunhnak

A tanglei hnaṭuannak (operations) hna hi nambat tlar (list of numbers) cungah tuah hna:

• Nambat unbalanced (odd numbers) 5 unnak list ser
• Nambat balanced (even numbers) 5 unnak list ser
• List pahnih kha fonh (Combine)
• A hram (beginning) ah prime number 11, 17, 29 pawl telh
• List chungah element zeizat dah a um ti langhter (Report)
• A dongh bik nambat 3 kha 100, 200, 300 in thlen
• List chung nambat vialte hlonh (Delete all numbers)
• List dihlak hrawh (Delete the list)

Program

# 1. Nambat unbalanced (odd numbers) 5 unnak list sernak
a = [1, 3, 5, 7, 9] 
print(a) 

# 2. Nambat balanced (even numbers) 5 unnak list sernak
b = [2, 4, 6, 8, 10] 
print(b) 

# 3. List pahnih kha fonh (combine) nak
a = a + b 
print(a) 

# 4. A hram (beginning) ah prime number 11, 17, 29 pawl telh nak
a = [11, 17, 29] + a 
print(a) 

# 5. List chungah element zeizat dah a um ti rel (report) nak
num = len(a) 
print(num) 

# 6. A dongh bik nambat 3 kha 100, 200, 300 in thlen (replace) nak
a[num-3:num] = [100, 200, 300] 
print(a) 

# 7. List chung nambat vialte hlonh (delete all) nak
a[:] = [ ] 
print(a) 

# 8. List dihlak hrawh (delete list) nak
del a

Output

[1, 3, 5, 7, 9] 
[2, 4, 6, 8, 10] 
[1, 3, 5, 7, 9, 2, 4, 6, 8, 10] 
[11, 17, 29, 1, 3, 5, 7, 9, 2, 4, 6, 8, 10] 
13 
[11, 17, 29, 1, 3, 5, 7, 9, 2, 4, 100, 200, 300] 
[] 

Problem 8.3

Stack data structure pakhat tuah ning (implement) tialnak: Stack cu Last In First Out (LIFO) list a si i, thil telh (addition) le hlonh (deletion) kha a hmun khat (a donghnak lei) ah tuah a si.

Program

# stack - LIFO list 
s = [ ] # empty stack 
# push elements on stack 
s.append(10) 
s.append(20) 
s.append(30) 
s.append(40) 
s.append(50) 
print(s) 

# pop elements from stack 
print(s.pop( )) 
print(s.pop( )) 
print(s.pop( )) 
print(s)

Hrilhfiahnak zoh nak caah hika hi hmet

1. LIFO (Last In First Out): 'Avi' kha a hnu bikah kan thun (push), nain kan chuah (pop) tikah a hmasa bikah a rak chuak.
2. append(): Hi method hi Stack chungah thil thar Push nak caah kan hman.
3. pop(): Hi method nih hin a dongh bik i a ummi element kha a hrawh i, a hrawhmi kha a return (a langhter) colh.

Output

[10, 20, 30, 40, 50] 
50 
40 
30 
[10, 20] 

Problem 8.4

Queue data structure pakhat tuah ning (implement) tialnak: Queue cu First In First Out (FIFO) list a si i, thil telh (addition) kha a donghnak (rear end) ah tuah a si, thil hlonh (deletion) kha a hram (front end) ah tuah a si.

Program

    import collections 
    # Queue pakhat ser (deque hman in)
    q = collections.deque( ) 

    # Enqueue operations (A donghnak ah thil telh nak)
    q.append('Suhana') 
    q.append('Shabana') 
    q.append('Shakila') 
    q.append('Shakira') 
    q.append('Sameera') 
    print(q) 

    # Dequeue operations (A hram bik element hlonh/chuah nak)
    print(q.popleft( )) 
    print(q.popleft( )) 
    print(q.popleft( )) 
    print(q) 

Hrilhfiahnak

1. collections.deque( ): Queue hnaṭuannak caah a ran deuh nakhnga (efficiency) hi module hi kan hman.
2. append( ): List a donghnak (rear) ah min thar telh nak a si.
3. popleft( ): Queue a hram (front) i a ummi min kha a hmasa bik in hlonh nak a si.

Output

deque(['Suhana', 'Shabana', 'Shakila', 'Shakira', 'Sameera']) 
Suhana 
Shabana 
Shakila 
deque(['Shakira', 'Sameera']) 

Problem 8.5

10 in 100 karah random nambat 20 ser i list chungah thun ding. Mah list chungin 20 le 50 kar i a ummi nambat vialte hlonh (delete) ding. A tangmi list kha print tuah ding.

Program

    import random 

    a = [ ] 
    i = 1 
    # Nambat 20 ser ding (Na code ah 15 a si nain, 20 ah kan thlen)
    while i <= 20 : 
        num = random.randint(10,100) 
        a.append(num) 
        i += 1 

    print("A hramthawk list:", a) 

    # 20 le 50 kar i a ummi hlonh nak
    # Cinchiah: List chungin thil kan hlonh lio ah 'for loop' hman hi a hman tawn lo, 
    # a hnu lei ah list thar ser ning (list comprehension) kan cawng lai.
    for num in a[:] : 
        if num > 20 and num < 50 : 
            a.remove(num) 

    print("A tangmi list:", a)

Output

[64, 10, 13, 25, 16, 39, 80, 100, 45, 33, 30, 22, 59, 73, 83] 
[64, 10, 13, 16, 80, 100, 33, 22, 59, 73, 83] 

Hrilhfiahnak

1. random.randint(10, 100): 10 le 100 karah random nambat pakhat a lak (generate) nak a si.
2. a.remove(num): Nambat pakhat kha a hmuh hmasa biknak hmun ah a hlonh nak a si.
3. a[:]: Loop kan hman lio ah list kan thlen (modify) duh ahcun, a hrampi list (original) kha copy ([:]) in hman a him deuh, khatah cun nambat cheukhat a hmaih (skip) khawh.

Problem 8.6

3 x 4 matrix pahnih fonh khawhnak program pakhat tial ding.

Program

# Matrix pahnih sernak
    mat1 = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]] 
    mat2 = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]] 
    # A phi chiah nak ding matrix a lawngin ser hmasa
    mat3 = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]] 

    # A tlar (rows) vialte tler (iterate) nak 
    for i in range(len(mat1)) : 
        # A tler (columns) vialte tler nak 
        for j in range(len(mat1[0])) : 
            # A hmun aa khatmi element pahnih fonh i mat3 ah khumh
            mat3[i][j] = mat1[i][j] + mat2[i][j] 

    print(mat3)

Hrilhfiahnak

1. range(len(mat1)): Matrix chungah tlar (row) zeizat dah a um ti kha a rel i, cu zat cu loop a kalpi.
2. range(len(mat1[0])): Tlar khat (row) chungah tler (column) zeizat dah a um ti kha a rel.
3. mat3[i][j]: mat1 le mat2 i an nambat hmun (index) aa khatmi cio kha fonh in mat3 chungah a thun hna.

Output

[[2, 4, 6, 8], [10, 12, 14, 16], [18, 20, 22, 24]] 

Exercises

[A] A tanglei program hna i a chuak dingmi (output) kawl nak:

a.

msg = list('https://github.com/rose1996iv')(https://github.com/rose1996iv)
ch = msg[-1] 
print(ch) 

b.

msg = list('www.google.com') 
s = msg[4:6] 
print(s) 

c.

msg = 'Online Courses - Beacon' 
s = list(msg[:3]) 
print(s) 

d.

msg = 'Beacon Academy' 
s = list(msg[-5:-2]) 
print(s) 

e.

s = list('Beacon') 
t = s[::-1] 
print(t) 

f.

num1 = [10, 20, 30, 40, 50] 
num2 = num1 
print(id(num1)) 
print(type(num2)) 
print(isinstance(num1, list)) 
print(num1 is num2) 

g.

num = [10, 20, 30, 40, 50] 
num[2:4] = [ ] 
print(num) 

h.

num1 = [10, 20, 30, 40, 50] 
num2 = [60, 70, 80] 
num1.append(num2) 
print(num1) 

i.

lst = [10, 25, 4, 12, 3, 8] 
sorted(lst) 
print(lst)

j.

a = [1, 2, 3, 4] 
b = [1, 2, 5] 
print(a < b) 

[B] Attempt the following questions:

(a) A hnuai i thil pawl lakah hin a hlei (valid) mi Python List cu zeidah a si?

['List'] | {"List"} | ("List") | "List"

(b) A hnuai i code hi na run (execute) ahcun zeidah a cang lai?

s = list('Hello')
s[1] = 'M'

© A hnuai i code hman hnuah hin, lam dang zeiti dek in 30 le 40 hi hloh khawh an si rih lai?

num = [10, 20, 30, 40, 50]
del(num[2:4])

(d) A hnuai i list pawl lakah hin a hmaan lomi (INCORRECT) cu zeidah a si?

1. a = [0, 1, 2, 3, [10, 20, 30]]
2. a = [10, 'Suraj', 34555.50]
3. a = [[10, 20, 30], [40, 50, 60]]

(e) A hnuai i list num1 hman hin, num2 list cu zeitin dek na ser lai?

num1 = [10, 20, 30, 40, 50] 

Na duhmi num2 result: ['A', 'B', 'C', 10, 20, 30, 40, 50, 'Y', 'Z']

(f) Pekmi list: lst = [10, 25, 4, 12, 3, 8] Hi list hi a ngan bik in a hme bik (descending order) tlar tein zeiti dek na tuah lai?

(g) Pekmi list: lst = [10, 25, 4, 12, 3, 8]
30 hi hi list chungah a um le um lo zeiti dek na check lai?

(h) Pekmi list: lst = [10, 25, 4, 12, 3, 8] Hi list chungah hin 25 le 4 karah 30 kha zeiti dek na telh (insert) lai?

(i) Pekmi string: s = 'Hello' Hi biafang (string) hi list ['H', 'e', 'l', 'l', 'o'] ah zeiti dek na canter lai?

[C] Answer the following questions:

a. List pakhat ser le thlen ning Namba pa (odd integers) namba 5 a ummi list pakhat tial u. A voithumnak (third element) kha namba nu (even integers) namba 4 a ummi list pakhat in thlen u. Mah hnuah list vialte kha phelh (flatten) u i, a hme bik in a ngan bik (sort) tlar tein langhter u.

b. Namba umnak hmun (position) kawlning List pakhat chungah random in namba 20 a um tiah ruat u. Keyboard (input) in namba pakhat tial u i, mah namba cu list chungah a hmun (index) zeizat hna ah dah a um tiah report tial u.

c. A hlei mi (duplicates) hlohning List pakhat chungah namba 20 a um. List chung i namba aa khatmi (duplicates) vialte hlohtu program pakhat tial u.

d. Namba (+) le (-) thleidanning List pakhat chungah namba ttha (positive) le namba chia (negative) an um tti. List thar pahnih ser u—pakhat ah namba ttha (positive) vialte chiah i, a dang pakhat ah namba chia (negative) vialte chiah ding.

e. Biafang cafang ngan (uppercase) ah canterning List pakhat chungah biafang (strings) 5 a um. Mah biafang vialte kha cafang ngan (uppercase) ah a cantertu program tial u.

f. Temperature thlenninh (Fahrenheit to Celsius) Fahrenheit (F) in pekmi temperature list kha a tlukpitu Celsius (C) ah a cantertu program tial u.

g. A laifang namba (median) kawlning List chung i namba pawl an i tlar ning (order) thleng loin, mah list i a laifang namba (median value) kawlning program tial u.

h. Namba chia (negative) zat relning List chungah namba ttha le namba chia lawng an um. List chungah namba chia (negative numbers) zeizat dah a um tiah a reltu program tial u.

i. Biafang hmai bik cafang lakning List pakhat chungah biafang (words) tampi an um. List thar pakhat ser u i, mah list chungah cun a hmasa list i biafang pakhat cio i an hmai bik cafang (first character) kha khumh u.

j. Namba 10 chung i a hlei mi hlohning List pakhat chungah namba 10 a um. List chung i aa khatmi (duplicates) vialte hlohtu program tial u.

k. Mean, Median, le Mode kawlning Namba 10 a ummi list pakhat chungah a tlangpi (mean), a laifang (median), le a chuak tam bik (mode) kawltu program tial u.

---

Comments