# tasks:
# 1 create a nested list of integers in Python
# 2 write it to a csv file
# 3 read it back,
# 4(a) double one number... 4(b) every number


# 1 - manually create a straight forward nested list
ints=[
    [3,6,8,3],
    [1,8,2,6],
    [9,4,2,7]
    ]

# 1 - using "list comprehension" can be used to generate lists very quickly...
import random
i=[[random.randint(1,100) for each in range(10)] \
    for every in range(5)] # nested list containing 5 lists, each of 10 random numbers.
print(i)

#2
import csv

with open("ints.csv", 'w', newline='') as csvfile: #prepare csv file for writing
    writer = csv.writer(csvfile) # use the .writer() method to create a variable called writer that Python can write to.
    writer.writerows(ints)  # write the list to the file

#3
list_name=[]
with open("ints.csv") as csvfile:
    reader = csv.reader(csvfile)
    for row in reader:
        list_name.append(row)
print(list_name)

###4(a) double one number
##ints[2][3]=int (ints[0][1])*2
##
###4(b) every number
##num_rows=len(ints)
##num_cols=len(ints[0]) #length of 1st row gives you #columns
##for row in range(0,num_rows):
##    for col in range(0,num_cols):
##        ints[row][col]=int (ints[row][col])*2
##print(ints)