cycle

  • Can execute the same thing multiple times ###while loop
whileCondition: Something to be done repeatedlyCopy the code
  • Example 1: Print 10 times I like you
i = 1
while i <= 10:# loop condition
    print("I like you.")
    i+=1# I is incremented by 1 each time through the loop. Until I is equal to 11, it doesn't satisfy the loop condition. Cycle to stop
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The above code runs as follows:

The while loop is nested

  • There’s a while loop inside a while loop
i = 1# Control the outside while loop
while i <= 9:
    j = 1# Control the while loop inside
    while j <= i:#while loop inside a while loop
        print("%d*%d=%d"%(j,i,i*j),end="\t")# add an end to print without newlines
        j+=1
    print("")# print empty for line feed
    i+=1
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The above code runs as follows:

Infinite loop

  • It goes on and on and on
while True: Something to do over and over againCopy the code

The for loop

  • Like the while loop, for can also be a loop. Simpler than while
for i inStrings, tuples, lists, ranges (): Things to do over and over againelse: The loop condition is not metCopy the code
  • Loop over the string
name = "python"
for i in name:
    print(i)# prints every character in the string
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The above code runs as follows:

  • With the range (start, end, step)

    • Start: the start value. The loop includes the start value
    • End: Termination value, loop does not include termination value
    • Step: step length

  • Step 1

for i in range(1.5.1) :# Start value :1 End value :5 Step size :1
    print(i)
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The above code runs as follows:

  • Step 2
for i in range(1.5.2) :# Start value :1 End value :5 Step size :2
    print(i)Print every 2
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The above code runs as follows:

The for loop is nested

  • There’s a for loop inside a for loop
for i in range(1.10) :The default step size is 1
    for j in range(1,i+1) :# I is 9 at most, 9 times 9 so I have to add 1
        print("%d*%d=%d"%(j,i,i*j),end="\t")
    print("")# a newline
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The above code runs as follows:

Break and continue

  • Can only be used in loops, break to end a loop
  • Used only in loops, continue terminates the current loop, followed by the next loop
  • break
for i in range(1.10) :if i == 6:# The loop ends when I is equal to 6
        break
    print(i)

While I < 10: if I == 6: break print(I) I +=1"
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The above code runs as follows:

  • continue
for i in range(1.10) :if i == 6:# loop this loop when I is equal to 6, and then the next loop
        continue
    print(i)

While I < 9: I +=1 if I == 6: continue print(I)"
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The above code runs as follows: