For Loop
A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string). |
For Loop - String
For i in "Color":
print(i)
>>> C
>>> o
>>> l
>>> o
>>> r
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For Loop - Dictionary
Car = {
"brand": "Ford",
"model": "Focus",
"year": 2013
}
for i in Car:
print(i)
>>> brand
>>> model
>>> year
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In this example we only print the keys of the dictionary, in the next example we will print the value of each key. |
for i in Car:
print(Car[i])
>>> Ford
>>> Focus
>>> 2013
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For Loop - Tuple
RYB_color = ("Red","Yellow","Blue")
for i in RYB_color:
print(i)
>>> Red
>>> Yellow
>>> Blue
|
For Loop - List
RYB_color = ["Red","Yellow","Blue"]
for i in RYB_color:
print(i)
>>> Red
>>> Yellow
>>> Blue
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The break Statement
for i in RYB_color:
if(i == "Yellow"):
break
print(i)
>>> Red
|
With the break
statement we can stop the loop before it has looped through all the items. In this example the loop stopped when the item is equal to "Yellow" |
The continue Statement
for i in RYB_color:
if(i == "Yellow"):
continue
print(i)
>>> Red
>>> Blue
|
With the continue
statement we can stop the current iteration of the loop, and continue with the next. |
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The range() Function
for i in range(3):
print(i)
>>> 0
>>> 1
>>> 2
|
The range(n)
is a function that returns a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and ends at (n -1)
. |
for i in range(2,5):
print(i)
>>> 2
>>> 3
>>> 4
|
In this example range(j,n)
returns a sequence of numbers, starting from j
and incremented by 1 (by default), and ends at (n - 1)
. |
for i in range(2,10,3):
print(i)
>>> 2
>>> 5
>>> 8
|
In this example range(j,n,k)
returns a sequence of numbers, starting from j
and incremented by k
and ends at (n - 1)
. |
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Else in For Loop
for i in range(3):
print(i)
else:
print("finally finished !")
>>> 0
>>> 1
>>> 2
>>> finally finished !
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Nested Loops
list_1 = ["Data" , "Machine learning"]
list_2 = ["Scientist","Engineer"]
for i in list_1:
for j in list_2:
print(i,j)
>>> Data Scientist
>>> Data Engineer
>>> Machine Learning Scientist
>>> Machine Learning Engineer
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The pass Statement
for i in RYB_color:
pass
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for loops cannot be empty, but if we for some reason have a for loop with no content, we can put in the pass statement to avoid getting an error. |
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