TillReg

AdvancedTutorials/1_Generators.py

@@ -4,3 +4,61 @@
 # When an iteration over a set of item starts using the for statement, the generator is run. Once the generator's function code reaches a "yield" statement, the generator yields its execution back to the for loop, returning a new value from the set. The generator function can generate as many values (possibly infinite) as it wants, yielding each one in its turn.
 # Here is a simple example of a generator function which returns 7 random integers:
 
+import random
+
+def lottery():
+    # returns 6 numbers between 1 and 40
+    for i in range(6):
+        yield random.randint(1, 40)
+
+    # returns a 7th number between 1 and 15
+    yield random.randint(1, 15)
+
+for random_number in lottery():
+       print("And the next number is... %d!" %(random_number))
+
+
+
+import os
+pathofcars = os.path.abspath("cars.csv")
+
+def lineofCars(loc):
+     with open(loc,'r') as file:
+        for line in file:
+             yield line
+
+text = lineofCars(pathofcars)
+print(next(text))
+print(next(text))
+print(next(text))
+
+#Change the values of two variables
+a = 1
+b = 2
+a, b = b, a
+print(a, b)
+
+
+# Exercise
+# Write a generator function which returns the Fibonacci series. They are calculated using the following formula: The first two numbers of the series is always equal to 1, and each consecutive number returned is the sum of the last two numbers. Hint: Can you use only two variables in the generator function? Remember that assignments can be done simultaneously. The code
+
+
+# fill in this function
+def fib():
+    pass #this is a null statement which does nothing when executed, useful as a placeholder.
+    a, b = 1, 1
+    for num in range(6):
+        a, b = b, a+b
+        yield a + b
+
+# testing code
+import types
+if type(fib()) == types.GeneratorType:
+    print("Good, The fib function is a generator.")
+
+    counter = 0
+    for n in fib():
+        print(n)
+        counter += 1
+        if counter == 10:
+            break