multiplying a string
what does the following code do?
"hello " * 3
can you use this idea to print a triangle of "*" using just a single for loop?
for i in range(1, 10):
print("*" * i)
controlling precision with str.format()
can you print the value 10/3, with only 2 digits of precision?
- hint: use the .format() function
"{:.2f}".format(10/3)
CSV
here is some data in CSV (Comma Seperated Values) format:
name, age, country
avi cohen, 30, israel
ben hur, 25, united kingdom
can davidovich, 40, georgia
david ben shalem, 60, united states of america
efrat ben dagan levi, 25, united arab emirates
- print only the names of the people in this data, and nothing else
- note: don’t print commas
',' - hint: use
splitlines()andsplit()
- note: don’t print commas
-
print only the ages
-
print only country names
-
print only the last 3 lines (hint: use splicing)
-
print the data without the header (hint: use splicing)
-
print every second line, without the header (hint: use splicing)
- print a smaller csv that has just ages and countries, without the header and without names
data = """\
name, age, country
avi cohen, 30, israel
ben hur, 25, united kingdom
can davidovich, 40, georgia
david ben shalem, 60, united states of america
efrat ben dagan levi, 25, united arab emirates
"""
# a
for line in data.splitlines()[1:] :
columns = line.split(',')
name = columns[0].strip()
print(name)
print()
# b
for line in data.splitlines()[1:] :
columns = line.split(',')
age = columns[1].strip()
print(age)
print()
# c
for line in data.splitlines()[1:] :
columns = line.split(',')
country = columns[2].strip()
print(country)
print()
# d
print('\n'.join(data.splitlines()[1: ]))
print()
# e
print('\n'.join(data.splitlines()[-3: ]))
print()
# f
print('\n'.join(data.splitlines()[1::2]))
print()
#g
for line in data.splitlines()[1:]:
age_country = line.split(',')[1:]
print(', '.join(age_country))
printing receipts
lets print a simple receipt using the .format() function the receipt will have 4 lines, looking like this:
cost : 362.50 NIS
vat : 17.00 %
vat : 61.62 NIS
total : 424.12 NIS
to determine the cost and the vat, lets use random numbers. use the following code:
import random
cost_nis = round(random.normalvariate(200, 50), 2)
vat_percent = random.randint(160, 180) / 10
# print(cost_nis, vat_percent)
compute the vat in NIS and the total and print the receipt
- NOTE: make sure that the numbers in the receipt are nicely aligned to make it readble!
- HINT: use the
str.format()function, read the specification or go through some examples to get the hang of this mini-langauge
import random
cost_nis = round(random.normalvariate(200, 50), 2)
vat_percent = random.randint(160, 180) / 10
# print(cost_nis, vat_percent)
receipt = """\
cost : {:6.2f} NIS
vat : {:6.2f} %
vat : {:6.2f} NIS
total : {:6.2f} NIS
""".format(cost_nis, vat_percent, cost_nis * vat_percent / 100, cost_nis + cost_nis*vat_percent/100)
print(receipt)
** a full receipt
given a menu with prices that can look like this:
prices = {
"steak" : 150,
"omelet" : 25,
"coca cola" : 12,
"orange juice" : 16,
"pizza" : 49,
"hamburger" : 59,
"pita" : 1.5,
"tomato salad" : 13.5
}
and an a list containing an order from a table, such as:
order = ["steak", "steak", "pita", "pizza", "coca cola"]
use a for loop to print a full receipt
steak : 150.00 NIS
steak : 150.00 NIS
pita : 1.50 NIS
pizza : 49.00 NIS
coca cola : 12.00 NIS
----------------------------
cost : 362.50 NIS
vat : 17.00 %
vat : 61.62 NIS
total : 424.12 NIS
### useful: data
prices = {
"steak" : 150,
"omelet" : 25,
"coca cola" : 12,
"orange juice" : 16,
"pizza" : 49,
"hamburger" : 59,
"pita" : 1.5,
"tomato salad" : 13.5
}
order = ["steak", "steak", "pita", "pizza", "coca cola"]
cost = 0
part1 = ""
for item in order:
price = prices[item]
cost += price
line = "{:15}: {:6.2f} NIS\n".format(item, price)
part1 += line
part1 += '-' * 28 + '\n'
vat = 17
part2 = """\
cost : {:6.2f} NIS
vat : {:6.2f} %
vat : {:6.2f} NIS
total : {:6.2f} NIS
""".format(cost, vat, cost * vat / 100, cost + cost*vat/100)
print(part1 + part2)