For and while loops

Intermediate Python for Finance

Kennedy Behrman

Data Engineer, Author, Founder

Repeating a code block

CUSIP

037833100

17275R102

68389X105

SYMBOL

AAPL

CSCO

ORCL

Loops.

For loop

While loop

Statement components

<Control Statement>
    <Code Block>

execution 1

execution 2

execution 3

For loops

for <variable> in <sequence>:

for x in [0, 1, 2]:

d = {'key': 'value1'}
for x in d:

for x in "ORACLE":

List example

for x in [0, 1, 2]:
    print(x)

0
1
2

Dictionary example

symbols = {'037833100': 'AAPL',
           '17275R102': 'CSCO'
           '68389X105': 'ORCL'}
for k in symbols:
    print(symbols[k])

AAPL
CSCO
ORCL

String example

for x in "ORACLE":
    print(x)

O
R
A
C
L
E

While control statements

while <expression>:

While example

x = 0

while x < 5:
    print(x)
    x = (x + 1)

Infinite loops

x = 0

while x <= 5:
     print(x)

Skipping with continue

for x in [0, 1, 2, 3]:
   if x == 2:
       continue
   print(x)

0
1
3

Stopping with break.

while True:
    transaction = get_transaction()
    if transaction['symbol'] == 'ORCL':
        print('The current symbol is ORCL, break now')
        break
    print('Not ORCL')

Not ORCL
Not ORCL
Not ORCL
The current symbol is ORCL, break now

Let's practice 'for' and 'while' loops!

Intermediate Python for Finance