# 1.First of all

My programming is based on MATLAB. When I started Python, there was a tough time because ** How to use For statements ** was very different from MATLAB. Today, I'll organize how to use Python's For statement.

# 1.1. For statement in Matlab

Format for variable = initial value: incremental: final value statements end

You must declare a for variable and enter its initial value: final value.

``````x = ones(1,10);

for n=2:6
x(n) = 2 * x(n-1);
end
``````

# 2. For statement in Python

Format for variable in list (or Tuple, Dictionary, etc.): statements

Note that, like Matlab, ** the initial value of a variable: declare a list, not the final value **. The concept of this part is very different.

## 2.1. Typical For statement

Create a list and print its elements.

``````test_list = ['one','two','three']
for i in test_list: #<-one, two,Substitute three in order for i.
print(i)
``````

Result

one two three

## 2.2. Various For statements

If the list element is Tuple

``````a = [(1,2),(3,4),(5,6)]

for (first, last) in a:
print('first element:', first)
print('last element :', last)
print('sum of first and last element =', first + last)
``````

Result

first element: 1 last element : 2 sum of first and last element = 3 first element: 3 last element : 4 sum of first and last element = 7 first element: 5 last element : 6 sum of first and last element = 11

## 2.3. Application

Suppose you take a test for 5 students. If the test score exceeds 60 points, it will be passed. If not, it will be rejected. Create a program that displays pass / fail according to the test score.

``````
score = [90,25,67,45,80]　#Test score

number = 0 #Numbers given to students
for mark in score: #<- 90,25,67,45,Substitute 80 in order for mark.
number = number + 1
if mark >= 60:
print("{:d}The second student has passed.".format(number))
else:
print("{:d}The second student fails.".format(number))
``````

Result

The first student has passed. The second student fails. The third student has passed. The fourth student fails. The fifth student has passed.

## 2.4. Frequently used range ()

The for statement is often used with a function called range that automatically creates a list of numbers.

``````ar = range(1,11) %<- 1,2,3,4,5,6,7,8,9,10
``````

Note that ars created with range () are ** range objects, not lists **.

``````type(ar)
``````

Result

range

Now let's use the for statement and range () to create the code to find the sum from 1 to 10.

``````sum = 0
for i in range(1,11):
sum = sum + i

print(sum)
``````

Result

55

If the score is 60 or more, the code that outputs the sentence "Pass" can be rewritten as follows.

``````score = [90,25,67,45,80]

for number in range(len(score)):
if score[number] >= 60:
print("{:d}The second student has passed.".format(number))
else:
print("{:d}The second student fails.".format(number))
``````

Result

The 0th student has passed. The first student fails. The second student has passed. The third student fails. The fourth student has passed.

## 2.5. Put a for statement in the list

This code creates a list called a and stores the result of multiplying each element by 3 in a list called result.

``````a = [1,2,3,4]
result = []
for yoso in a:
result.append(yoso*3)

print(result)
``````

Result

[3, 6, 9, 12]

This can be made into a simple code as follows by using the method of putting a for statement in the list.

``````a = [1,2,3,4]
result = [num * 3 for num in a]
``````

Result

[3, 6, 9, 12]

If you triple it to an even number, you can add an if statement as follows.

``````a = [1,2,3,4]
result = [num * 3 for num in a if num%2 ==0]
``````

Result

[6, 12]

# 3. Summary

I tried to organize various usages of Python for statement. It's deep.