1.Add filter practice

2.Add prime_number

Signed-off-by: Jackey <smjjackey@sina.com>

Author: mjjackey

filter_practice.py

@@ -0,0 +1,9 @@
+def is_palindrome(n):
+    return all(str(n)[i]==str(n)[len(str(n))-1-i] for i in range(int(len(str(n))/2)))
+
+output = filter(is_palindrome, range(1, 1000))
+print('1~1000:', list(output))
+if list(filter(is_palindrome, range(1, 200))) == [1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191]:
+    print('测试成功!')
+else:
+    print('测试失败!')

list_try.py renamed to list_set_try.py

@@ -0,0 +1,48 @@
+import math
+def generate_prime():
+    n=100
+    pri_num_list=[]
+    for num in range(2, n + 1): # the range of candidate numbers
+        if all(num % j != 0 for j in range(2, int(math.sqrt(num))+1)):  # Try divide 2 to sqrt(num)
+            pri_num_list.append(num)
+    print(len(pri_num_list),pri_num_list)
+
+def generate_prime2():
+    n = 100
+    pri_num_list = []
+    for num in range(2,n+1): # the range of candidate numbers
+        flag = True
+        for j in range(2, int(math.sqrt(num)+1)):  # Try divide 2 to sqrt(num)
+            if(num%j==0):
+                flag=False
+                break
+        if(flag):
+            pri_num_list.append(num)
+    print(len(pri_num_list), pri_num_list)
+
+def generate_prime3():
+    n = 100
+    pri_num_list = []
+    for num in range(2, n + 1):
+        flag1 = True
+        for j in range(2, int(math.sqrt(num) + 1)): # Try divide 2 to sqrt(num)
+            flag2=True
+            ### check whether j is a prime ###
+            for k in range(2, int(math.sqrt(j) + 1)):
+                if (j % k == 0):
+                    flag2 = False # j is not a prime
+                break
+            if(flag2==False):
+                continue
+            ### check whether j is a prime ###
+            
+            if(num % j==0): # j is a prime
+                flag1=False # num is not a prime
+                break
+        if (flag1):
+            pri_num_list.append(num)
+    print(len(pri_num_list), pri_num_list)
+
+generate_prime()
+generate_prime2()
+generate_prime3()

prime_number.py

@@ -0,0 +1,30 @@
+"""
+埃氏筛法求素数, from https://github.com/michaelliao/learn-python3/blob/master/samples/functional/prime_numbers.py
+"""
+def main():
+    for n in primes():
+        if n < 1000:
+            print(n)
+        else:
+            break
+
+def _odd_iter():
+    n = 1
+    while True:
+        n = n + 2
+        yield n
+
+def _not_divisible(n):
+    return lambda x: x % n > 0
+
+def primes():
+    yield 2
+    it = _odd_iter()
+    # print(it)  # one element 2 and generator object
+    while True:
+        n = next(it)
+        yield n
+        it = filter(_not_divisible(n), it)
+
+if __name__ == '__main__':
+    main()