Pemahaman senarai menawarkan sintaks yang lebih pendek apabila anda ingin membuat senarai baharu berdasarkan nilai senarai sedia ada. (rujuk-https://www.w3schools.com/python/python_lists_comprehension.asp)
Contoh:1
Kaedah:1
fruits = ["apple", "banana", "cherry", "kiwi", "mango"] newlist = [] for x in fruits: if "a" in x: newlist.append(x) print(newlist)
Kaedah:2(menyeluruh)
fruits = ["apple", "banana", "cherry", "kiwi", "mango"] newlist = [x for x in fruits if "a" in x] print(newlist)
Output:
['apple', 'banana', 'mango']
Contoh:2
l = [10,20,30,40] newlist = [] #using normal loop for num in l: newlist.append(num**2) print(newlist) #using loop in comprehensive way newlist = [num**2 for num in l] print(newlist)
Output:
[100, 400, 900, 1600] [100, 400, 900, 1600]
Latihan:
1.Cari nombor yang serupa daripada 2 senarai dan nombor berbeza daripada 2 senarai yang sama.
l1 = [10,20,30,40]
l2 = [30,40,50,60]
Dapatkan output ini:
a) 30,40
#30,40 l1 = [10,20,30,40] l2 = [30,40,50,60] #normal method for num in l1: for no in l2: if num== no: print(num,end=' ') #comprehensive print([num for num in l1 for no in l2 if num==no])
output:
[30, 40]
b) 10,20,50,60
l1 = [10,20,30,40] l2 = [30,40,50,60] #comprehensive output = [num for num in l1 if num not in l2] output = output + [num for num in l2 if num not in l1] print(output) #normal method for num in l1: if num not in l2: print(num,end=' ') for num in l2: if num not in l1: print(num,end=' ')
Output:
[10, 20, 50, 60] 10 20 50 60
2. Cari program untuk output yang diberikan dalam pendekatan komprehensif
l1 = [1,2,3]
l2 = [5,6,7]
Output:[(1, 5), (1, 6), (1, 7), (2, 5), (2, 6), (2, 7), (3, 5), (3, 6) , (3, 7)]
l1 = [1,2,3] l2 = [5,6,7] l = [(i,j) for i in l1 for j in l2 if i!=j] print(l)
Output:
[(1, 5), (1, 6), (1, 7), (2, 5), (2, 6), (2, 7), (3, 5), (3, 6), (3, 7)]
3. Cari atur cara untuk output yang diberikan:
s = "a1b2c3"
keluaran: abc123
Kaedah:1
s = "a1b2c3" alpha_list = [] num_list = [] for letter in s: if letter.isalpha(): alpha_list.append(letter) else: num_list.append(letter) print("".join(alpha_list+num_list))
Kaedah:2
s = "a1b2c3" letter=''.join([i for i in s if i.isalpha()]) no=''.join([i for i in s if i.isdigit()]) print(letter+no)
Output:
abc123
4. Cari atur cara untuk output yang diberikan:
s = "a4k3b2"
output: aeknbd
s = "a4k3b2" i = 0 while i<len(s): first = s[i] second = int(s[i+1]) print(first, chr(ord(first)+second),sep='',end='') i+=2
Output:
aeknbd
Penjelasan:
-->Nilai ASCII pertama diperoleh menggunakan ord(pertama), dan kedua ditambahkan padanya untuk mencari aksara baharu.
-->ord() digunakan untuk mencari nilai ASCII.
-->chr() menukar nilai ASCII-->aksara.
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