Basics.ipynb

Kernel: Python 3 (Anaconda)

Names first

import numpy as np
import pandas as pd

What's a variable?

x = 'hello'
print('hello')

hello

x

'hello'

How to print in Jupyter?

print(x)
x

hello

'hello'

Basic types: String? Integer? Float?

astr = 'yellow'
another_str = "yellow"
aint = 4
another2_str = str(aint)
multiple_line_str = """
asgashdsj
sdajfdfsjfdjjsfjdsjfsdj
fsjfdsjsdfj
"""

afloat = 10.2

a = 10.
b = '45'
c = 1337

Higher level types: Tuple? List? Dictionary?

atup = (1, 2)
atup2 = 1, 2

atup3 = tuple(atup)

alist = [5, 5, 6, 7]
adict = {'key1': [6, 3], 'key2': [5, 4]}
mypairs = ((1,"Hi there"), (2, "Good-bye"))
adict2 = dict(mypairs)
adict2

{1: 'Hi there', 2: 'Good-bye'}

atup_of_lists = ([1, 2], (1, 2), adict2)
alist_of_tups = [(1, 2), [1, 2]]
adict_of_lists_and_tups = {'x': alist, 'y': atup} # NOT ABLE TO SORT

How to check the type? And length!

print(type(atup))
print(type(atup[0]))

alist = [(5, 4, [3, 4, 5, 6, 7, 8, 8], 2, 1), 5, 6, 7]

print(alist[0][2])

<class 'tuple'>
<class 'int'>
[3, 4, 5, 6, 7, 8, 8]

Subscript/slice/subselect/reverse

alist = [1, 2, 3, 4, 5]
alist_rev = alist[::-1]

alist = np.array([[1, 2, 3], [4, 5, 6]])

print(np.shape(alist)) # get dimensions
print(alist[1][0])
print(alist[1, 0]) # only works if np array


atup_sub = atup[0]
alist_sub = alist[0:2]
adict_sub = adict['key1']
alist_sub

(2, 3)
4
4

array([[1, 2, 3],
       [4, 5, 6]])

Other types: np.array?, pd.DataFrame?

nparr = np.array(alist)
pddf = pd.DataFrame(adict)

One big difference between np.array and lists

alist = [1, 2, 3, 4]
aint = 2
alist_aint = alist * aint
nparr_aint = nparr * aint
alist_aint, nparr_aint

([1, 2, 3, 4, 1, 2, 3, 4], array([[ 2,  4,  6],
        [ 8, 10, 12]]))

Format a string!

afloat_fmt = '{0:0.2f} hi {1}'.format(afloat, aint)
aint_fmt = '{0:5d}'.format(aint)
astr_fmt = '{0}'.format(astr)

test_fmt = '{0:50.24f}'.format(np.pi)
test_fmt2 = '{0:<050f}'.format(15.2152151251)
test_fmt3 = '{0:25d}'.format(15)
# order number, colon (syntax), 0 = fill empty with zeros, number after decimal number of decimal places
# name format~~~
otherway_fmt = '{anumber:50.24f}, {anumber:25.24f}'.format(anumber=afloat)

afloat_fmt
# test_fmt, test_fmt2, test_fmt3, otherway_fmt

'10.20 hi 4'

aint = 2
afloat = 3.5
astr = 'hyoelllo'
'random something 2 3.5 hyo'
pleasedonthardcode = 'random something 2 3.5 hello'
afloat_aint_astr_fmt = 'random something {0} {1} {2}'.format(aint, afloat, astr)
afloat_aint_astr_fmt
afloat_aint_astr_fmt = \
    'random something {aint} {afloat} {astr}'.format(
    aint=aint, afloat=afloat, astr=astr)
afloat_aint_astr_fmt

'random something 2 3.5 hyoelllo'

'{0:04.2f}'.format(np.pi), '{0:0.2f}'.format(np.pi), \
'{0:07.2f}'.format(np.pi), '{0:0.6f}'.format(np.pi)

('3.14', '3.14', '0003.14', '3.141593')