This page will go through different types of Looping. This, in combination with IF statements is a powerful combination and works as a great founding block to any programmer regardless of the programming language.
However, for massive loops I would consider starting to use array matrix operations instead as that will go much faster. 1 line of code to add a "column calculation" versus looping through the entire matrix.
Loops can be divided in to two types of loops: For Loops or While Loops. For Loops are definitely the ones I use the most. Whilst creating While loops can be a good thing, sometimes it can also get your code into an annoying endless circle as it is basically just a 'For loop' to infinity.
For Loops examples
# Looping 0 to 9, which is 10 times. for x in range(10): print(x)
the "Range" syntax above is useful for looping to a number or between certain numbers. In python, the first index is 0. which is recurring for many other python syntaxes. The range syntax works like the following.
class range(start, stop[, step])
This means that we can use the second class option above to write the python statement so that our loop starts at 1 and goes to 10. Note that our first loop stopped at 9 so in order for our loop to stop and include 10 we need to change the stop number to 11 like below.
# Looping 1 to 10, which is 10 times. for x in range(1,11): print(x)
We can also skip numbers according to the second class for the "Range" syntax by adding one more parameter. [step]
# Looping 1 to 10, with an interval of 2, which technically gives us 9 as our last number. for x in range(1,11,2): print(x)
# Looping 10 to 2. 9 times as last number is 2. for x in range(10,1,-1): print(x) # Looping 10 to 1. 10 times as last number is 1. for x in range(10,0,-1): print(x)
Loop through a list.
# Will write out each textfield. MyVar = ["Please", "Fix", "Thx"] for x in MyVar: print(x)
Loop through a word.
# Will write out each letter in the word. MyVar = "PleaseFixThx" for x in MyVar: print(x)
Double looping (a loop in a loop.. I know, Inception right!!)
The inner y loop will be executed completely before going to the next iteration of the outer loop.
# Double looping. for x in range(1,3): for y in range(1,3): print (x * y) # Result: 1, 2, 2, 4
# need to increment i with 1 for each loop. # otherwise this loop will continue forever. # increment of i could also have been written as i = i + 1. i = 1 while i < 10: print(i) i += 1
Loop with IF statement.
# Will only write out the letter "F" MyVar = "PleaseFixThx" for x in MyVar: if x == "F": print(x)
Loop with Break statement.
The "Break" syntax will stop the loop execution when a condition is met.
# Will write out each letter in the word until and including the letter "F". MyVar = "PleaseFixThx" for x in MyVar: print(x) if x == "F": break
Loop with Continue statement.
The "Continue" syntax skips and jumps to the next iteration.
# Will skip "Fix" and write out "Please" and "Thx" MyVar = ["Please", "Fix", "Thx"] for x in MyVar: if x == "Fix": continue print (x)
Learn more about Python here for all my posts: https://www.pls-fix-thx.com/python
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