#!/usr/bin/env python3 # vereda - notices and documentation at the end of the file def main () : # "main" is called from the end of the file '''Vereda''' # it simulates the C [main function] init () # initialisation hello_world_function () # [function]{Function_(computer_programming)} # * objects variable () # [variable] {Variable (computer science)} listz,tuplez,setz,dictz = data_structure () # [data structure] data_structure_def () # new data structures definition variable_scope () # local nonlocal global # * [control flow] control_flow_if () # [conditional] {Conditional_(computer_programming)} control_flow_switch () # [switch statement] control_flow_loop_for (listz,tuplez,setz,dictz)# for loop [loop statement] control_flow_loop_while () # while loop control_flow_error_handling () # LBYL EAFP # * function function_static () # first call [static variable] function_static () # second call a,b = function_fix ('arg1','arg') # fix number of arguments function_var ('One','Two') # first call | variable number of arguments function_var ('One','Two','Three') # second call function_kwarg ( a='AA', b='BB' ) # kwarg: keyword argument, arbitrary number of arguments function_call_by () # call by value, reference and object # Python Standard Library https://docs.python.org/3/library [library] standard_library_built_in () # no import https://docs.python.org/3/library/functions.html standard_library_modules () # import required external_modules () # install and import | packages # * external read and write command_line_arguments () # get arguments kinput = keyboard_input (False) # kinput: keyboard input | to enable set to "True" text = readfile () # read whole text file appendfile (kinput,text) # append to file html () # generate HTML csv () # CSV (Comma Separated Values) record_jar () # record-jar format json () # JSON sqlite () # SQLite csv_to_sqlite () # read CSV into SQLite pickle_ex () # binary format [serialisation] zipdir () # recursively zip directory # * packages matplotlib_ex () # matplotlib.org numpy_ex () # numpy.org pandas_ex () # pandas.pydata.org # * miscellaneous generate_documentation () # zorro module documentation exit (0) #------------------------------------------------#-------------------------------------------# def init () : # https://docs.python.org import sys from os import environ from platform import python_version # https://docs.python.org/3/library/platform.html#module-platform from zorro import ZM , TIMESTAMP , mkdir , __file__ # zorro is a private module VERVERSION = 1 # Vereda version global VERHOME , ZM , TIMESTAMP , DOT # avoid globals | constants not too bad # no [constants] in Python: convention capitals are constants VERHOME = environ ['VERHOME'] # VERHOME: vereda home | set by "source /foo/ver/lib/setup" DOT = VERHOME + '/output' # DOT: Directory OutpuT mkdir ( DOT ) # create directory if it does not exist file_stdout = ( DOT + '/stdout.txt' ) sys.stdout = open ( file_stdout , 'w' ) # redirect standard output to file print ( '* Vereda standard output' ) print ( '\n* init' ) print ( 'Timestamp: ' , TIMESTAMP ) # yymmdd-hhmmss print ( 'Vereda version =' , VERVERSION ) print ( 'Vereda file =', environ['_'] ) print ( 'Zorro version =' , ZM ['version'] ) # ZM:Zorro metadata print ( 'Zorro file =' , __file__ ) print ( 'Python version =' , python_version ()) print ( 'Python file =' , sys.executable) #------------------------------------------------#-------------------------------------------# def hello_world_function () : print ('\n* hello_world_function') #------------------------------------------------#-------------------------------------------# def variable () : # docs.python.org/3/library/stdtypes.html '''Main built-in scalar types''' print ( '\n* variable\n' , variable.__doc__ ) i = 42 # integer id:s value:42 type:integer f = 3.14 # float id:s value:3.14 type:float s = 'hello' # string id:s value:hello type:string b = True # boolean id:s value:True type:boolean x = 2 + 9 - 3 * 4 / 2 x += 1 # y += n s = '44' # string i = int (s) # convert string to integer | float () y = 'Hello' + ' world' # concatenate strings print ( y ) print ( 'slice y[2:4] = ' , y[2:4]) # https://realpython.com/lessons/string-slicing print ( i , f , s , b ) #------------------------------------------------#-------------------------------------------# def data_structure () : '''Main built-in data structure types''' print ( '\n* data_structure\n' , data_structure.__doc__ ) # [array] [array dimension] listz = [ 'zero' , 1 , 'two' , 'two' ] # list : ordered | duplicates | mutable tuplez = ( 'Zero' , 1 , 'Two' , 'Two' ) # tuple : ordered | duplicates | immutable setz = { 'zero' , 1 , 2 } # set : unordered | no duplicates | mutable dictz = { # dict : ordered | no duplicates | mutable 'a' : 'zero' , # [associative array] [key-value] 1 : 'one' , '2' : 'TWO' } a2 = [ # two dimensinal array, list of lists [ '00' , '01' ], # [matrix] [ '10' , '11' ], [ '20' , '21' ] ] s = listz [0] # s = zero s = tuplez [0] # s = Zero n = len (setz) # n = 3 | items no referable by index s = dictz ['2'] # s = TWO print ( 'Two dimensional array' ) print ( 'All: ', a2 ) print ( 'Row 1: ', a2[1] ) print ( 'Element 2,1: ', a2[2][1] ) print ( '\nDictionary: ', dictz ) # print the whole dict return listz,tuplez,setz,dictz #------------------------------------------------#-------------------------------------------# def data_structure_def () : # [compound data type] {wiki/Typedef} print( '\n* data_structure_def' ) struct = { 'a' : None , 'b' : None } # Algorithms + Data Structures = Programs s = { 'a': 11 , 'b':22.0 } print( s ) print( s['a'] ) #------------------------------------------------#-------------------------------------------# def variable_scope () : # realpython.com/python-namespaces-scope a = 88 # a: local | global | nonlocal #------------------------------------------------#-------------------------------------------# def control_flow_if () : '''Control flow with the conditional statement (if)''' print ( '\n* control_flow_if\n' , control_flow_if.__doc__) i = 7 if i == 7 : s = 'seven' if i == 8 : s = 'eight' else : s = 'not eight' print (s) #------------------------------------------------#-------------------------------------------# def control_flow_switch () : '''Control flow with the switch statement (case)''' print ('\n* control_flow_switch' ) letter = 'a' match letter: case 'a' | 'e' | 'i' | 'o' | 'u' : print ( f'letter "{letter}" is a vowel') case 'y' : print ( f'letter "{letter}" may be a vowel') case _ : print ( f'letter "{letter}" is not a vowel') #------------------------------------------------#-------------------------------------------# def control_flow_loop_for (listz,tuplez,setz,dictz) : '''Loop through data arrays''' print ('\n* control_flow_loop_for') print ('list=' , end='') for i in listz : print (i , '|' , sep='' , end='') print ('\ntuple=' , end='') for i in tuplez : print (i , '|' , sep='' , end='') print ('\nset=' , end='') for i in setz : print (i , '|' , sep='' , end='') print ('\nrange=' , end='') for i in range (2,8,2): # range (start, stop, step) print (i , '|' , sep='' , end='') print ('') control_flow_loop_for_dict (dictz) #------------------------------------------------#-------------------------------------------# def control_flow_loop_for_dict (dictz) : '''Loop through several options of dictionary''' print ('\n* control_flow_loop_for_dict') print ('\nkey=' , end='') for k in dictz : # k:key value:dictz[k] print (k , '=' , dictz[k] , '|' , sep='' , end='') print ('\nkey-value=' , end='') for k , v in dictz.items () : # k:key v:value print (k , '=' , v , '|' , sep='' , end='') # v = dictz[k] print ('\ntuple=' , end='') for t in dictz.items () : # t: tuple print ( t , '|' , sep='' , end='') # key = t[0] | value = t[1] print () #------------------------------------------------#-------------------------------------------# def control_flow_loop_while () : '''While loop''' print ('\n* control_flow_loop_while ' ) i = 0 while i < 3 : print (i , '|' , sep='' , end='') i += 1 print () #------------------------------------------------#-------------------------------------------# def control_flow_error_handling () : print ( '\n* error_handling' ) a = None b = 0 if b == 0 : print ( 'Look Before You Leap (LBYL): no zero division' ) else : a = 1/b try : a = 1/b except : print ( 'Easier to ask for forgiveness than permission (EAFP): no zero division' ) print ( a ) #------------------------------------------------#-------------------------------------------# def function_static () : '''Simulating static local variable using function attribute''' print ('\n* function_static') # Python does not have static variables try : function_static.a += 1 # unassigned function_static.a raises exception except : function_static.a = 1 print ('except') print ( function_static.a ) #------------------------------------------------#-------------------------------------------# def function_fix (param1,param2) : # param: parameter '''Function with paramenters''' # number of parameters print ('\n* function_fix') return param2,param1 # switch the values # [call by value] [call by reference] # dev.to/adarshrawat7400/how-call-by-value-and-call-by-reference-work-in-python-am2 #------------------------------------------------#-------------------------------------------# def function_var ( *argv ) : # also: ( arg1 , *argv ) '''Function with variable number of arguments''' print ('\n* function_var') try : function_var.flag += 1 except : function_var.flag = 1 print ('except') # print only the first time the function is called print (argv) # parameter, but by convention "argv" #------------------------------------------------#-------------------------------------------# def function_kwarg ( **kwargv ) : # kwarg: keyword argument print ( '\n* function_kwarg' ) print ( kwargv) #------------------------------------------------#-------------------------------------------# def function_call_by () : '''Function call by value, reference and object ''' print ('\n* function_call_by') # inmutable objects : call by value # mutable objects : call by reference def change ( a , b ) : a = 2 # inmutable : value changes only inside func b.append (9) # mutable : value changes also outside func print ( 'Inside function :' , a , b , id(a) , id(b) ) # id: object identity a = 1 # integer : inmutable b = [8] # list : mutable print ( 'Outside function before :' , a , b , ' ' , id(a) , id(b) ) change ( a , b ) print ( 'Outside function after :' , a , b , id(a) , id(b) ) #------------------------------------------------#-------------------------------------------# def standard_library_built_in () : # https://docs.python.org/3/library/functions.html print ('\n* standard_library_built_in') s = 'Some string' # docs.python.org/3/library l = len (s) # function | len: length u = s.upper () # method of string | function vs. method # dot notation | object-oriented programming (OOP) print ( s , l , u ) #------------------------------------------------#-------------------------------------------# def standard_library_modules () : # import print ( '\n* standard_library_modules ' ) # docs.python.org/3/py-modindex.html import zorro # import the whole module print ( 'zorro module version=' , zorro.ZM ['version'] ) from zorro import ZM # import one item print ( 'zorro module rights=' ,ZM ['rights' ] ) import hello_mod # hello world module | private module hello_mod.world () print ( 'datetime, pre-installed module' ) from datetime import datetime cyear = int (datetime.now().strftime("%Y")) # cyear: current year | ex. 2023 print ('Current year:' , cyear) #------------------------------------------------#-------------------------------------------# def external_modules () : # install and import | Python Package Index (PyPI.org) ''' They must be installed Example of popular packages: NumPy, Matplotlib python3 -m pip install foo pip3 install foo''' print ( '\n* external_modules' , external_modules.__doc__) #------------------------------------------------#-------------------------------------------# def command_line_arguments () : print ( '\n* command_line_arguments' ) from sys import argv print ( argv ) #------------------------------------------------#-------------------------------------------# def keyboard_input (flag) : print ( '\n* read_input' ) '''Read input from the command line''' a = 'NO INPUT - set function to "True"' if flag : import sys print ( 'Type something: ' , end='' , file=sys.stderr ) a = input () b = 'You typed: [' + a + ']' print ( b ) return b #------------------------------------------------#-------------------------------------------# def readfile () : print ( '\n* readfile' ) from zorro import read_text fit = VERHOME + '/data/lane.txt' # fit: File InpuT return read_text (fit) # check existance before reading #------------------------------------------------#-------------------------------------------# def appendfile ( ki , text ) : print ( '\n* appendfile' ) from zorro import append_text fot = DOT + '/newlane.txt' # fot: File OutpuT append_text ( TIMESTAMP + '\n' + ki + '\n' + text + '\n\n' , fot ) #------------------------------------------------#-------------------------------------------# def html () : print ( '\n* html' ) buf = ''' Vereda ⌂

Vereda output

''' from shutil import copy copy ( VERHOME + '/lib/vereda.jpg' , DOT ) copy ( VERHOME + '/lib/vereda.css' , DOT ) copy ( VERHOME + '/lib/zorro.py' , DOT + '/zorro.py.txt' ) from zorro import write_text write_text ( buf , DOT + '/index.html' ) #------------------------------------------------#-------------------------------------------# def csv () : # print ( '\n* cvs' ) import csv fit = VERHOME + '/data/table.csv' # fit: File InpuT with open ( fit , newline='' ) as fo : row = csv.reader ( fo , delimiter = ',' ) table = list (row) from pprint import pprint # pretty printer docs.python.org/3.8/library/pprint.html pprint ( table ) #------------------------------------------------#-------------------------------------------# def record_jar () : # www.catb.org/esr/writings/taoup/html/ch05s02.html#id2906931 print ( '\n* record_jar' ) from zorro import read_record_jar fit = VERHOME + '/data/reja.txt' # fit: File InpuT reja = read_record_jar ( fit ) print ( 'type of reja:' , type (reja) ) print ( reja ) print ( reja[1] ) print ( reja[1]['Planet'] ,'\n' ) from pprint import pprint # pretty printer docs.python.org/3.8/library/pprint.html pprint (reja) #------------------------------------------------#-------------------------------------------# def json () : # text format [serialisation] '''JSON: widely used, human readable''' print ( '\n* json' ) # JSON: widely used, human readable from zorro import read_json , write_json # [marshalling] {Marshalling_(computer_science)} d = { 'a' : 'AAA' , 'b' : 'BBB' } fot = DOT + '/ex.json' # fot: File OutpuT write_json ( d , fot ) # if file exist, overwrite, not append print ( read_json (fot) ) #------------------------------------------------#-------------------------------------------# def sqlite () : print ( '\n* sqlite' ) import os from sqlite3 import connect dbfile = DOT + '/item.sqlite' if os.path.isfile (dbfile) : os.remove(dbfile) db = connect ( dbfile ) # db: db connector c = db.cursor () # c: cursor c.execute ( '\ create table items ( \ item varchar (20) \ , no int \ )') c.execute ( 'insert into items ( item , no ) values ( "apple" , 4 ) ') c.execute ( 'insert into items ( item , no ) values ( "orange" , 2 ) ') c.execute ( 'insert into items ( item , no ) values ( "bed" , 9 ) ') db.commit () c.execute ( 'select * from items' ) print ( c.fetchall () ) #------------------------------------------------#-------------------------------------------# def csv_to_sqlite () : print ( '\n* cvs_to_sqlite' ) import os from sqlite3 import connect import csv from zorro import basename from pprint import pprint ## read CSV file airq = VERHOME + '/data/air_quality_no2.csv' with open ( airq , newline='' ) as fo : row = csv.reader ( fo , delimiter = ',' ) table = list (row) ## make string "s" to create table s = 'create table air (' for fn in table [0] : # fieldnames in the first line | fn: fieldname s = s + fn + ' varchar (99),' s = s[:-1] + ')' # replace last character ',' by ')' ## make database and table dbfile = DOT + '/air.sqlite' if os.path.isfile (dbfile) : os.remove(dbfile) # delete database file, if exists db = connect ( dbfile ) # create database | db: db connector c = db.cursor () # c: cursor c.execute (s) # create table fields = ' '.join ( table[0] ) # convert list to string with the fieldnames del table[0] # delete first item in the list with the column names c.executemany ( "INSERT INTO air VALUES(?, ?, ?,?)", table) db.commit() c.execute ( 'select rowid , * from air where rowid <= 5' ) print ( 'file: output/' + basename (dbfile) ) print ( 'fields: rowid' , fields ) print ( 'rows 1 to 5:' ) pprint ( c.fetchall () ) #------------------------------------------------#-------------------------------------------# def pickle_ex () : # binary format [serialisation] print ( '\n* pickling_ex' ) # format only for Python import pickle # Pickle: only Python, binary (non human readable) d = { 'a' : 'AAA' , 'b' : 'BBB' } # unsafe as it can contain executable code d_p = pickle.dumps (d) # pickle to variable d_u = pickle.loads (d_p) # unpickle from variable print ( f"d={d}") print ( f"d_p={d_p}") print ( f"d_u={d_u}") fot = DOT + '/ex.pickle' # fot: File OutpuT with open ( fot , 'wb') as fo : # pickle to file pickle.dump (d , fo , pickle.HIGHEST_PROTOCOL) with open ( fot , 'rb') as fo : # unpickle from file d_f = pickle.load (fo) print ( 'd_f=' , d_f ) #------------------------------------------------#-------------------------------------------# def zipdir () : '''Recursively zip directory to a file''' print ( '\n* zipdir' ) from zorro import writezip dit = VERHOME + '/data' # dit: Directory InpuT fot = DOT + '/data.zip' # fot: File OutpuT writezip ( dit , fot ) print ( 'Output to "output/data.zip"' ) #------------------------------------------------#-------------------------------------------# def matplotlib_ex () : print ( '\n* matplotlib_ex' ) import matplotlib.pyplot as plt # matplotlib.org pypi.org from sys import modules plt.clf () # clear figure v = modules [plt.__package__].__version__ # v: matplotlib version plt.title ( 'Title | matplotlib version: ' + v ) plt.ylabel ( 'Y axis' ) plt.xlabel ( 'X axis' ) plt.text ( 2 , 4 , '⚫ (2,4)' ) plt.plot ( [1, 2, 3] , [1, 4, 9] ) plt.savefig ( DOT + '/plot.png' ) plt.savefig ( DOT + '/plot.pdf' ) #------------------------------------------------#-------------------------------------------# def numpy_ex () : print ( '\n* numpy_ex' ) import numpy as np # numpy.org import matplotlib.pyplot as plt # matplotlib.org/stable/tutorials/pyplot.html#annotating-text plt.clf () # clear figure t = np.arange ( 0.0 , 9.0 , 0.01 ) s = np.cos ( 2*np.pi*t ) line = plt.plot ( t , s , lw=2 ) plt.ylim (-2, 2) plt.annotate ( 'local max' , xy=(2, 1) , xytext=(3, 1.5) , arrowprops=dict(facecolor='red',shrink=0.05)) plt.savefig ( DOT + '/numerical.png' ) #------------------------------------------------#-------------------------------------------# def pandas_ex () : # pandas.pydata.org print ( '\n* pandas_ex' ) import pandas as pd # DataFrame : matrix print ( 'example 1' ) ## example 1: pandas.pydata.org) df = pd.DataFrame ( { # Series : column "Name": [ "Braund, Mr. Owen Harris", "Allen, Mr. William Henry", "Bonnell, Miss. Elizabeth", ], "Age": [22, 35, 58], "Sex": ["male", "male", "female"], } ) print ( df , '\n' ) print ( df ['Age'] , '\n' ) print ( 'Max age = ' , df ['Age' ].max() , '\n' ) print ( 'Describe = ' , df.describe () , '\n' ) print ( 'example 2' ) ## fit = VERHOME + '/data/table.csv' # fit: File InpuT table = pd.read_csv ( fit ) print (table , '\n' ) print ( table.info() , '\n' ) print ( 'example 3' ) ## example 3: air quality, from pandas.pydata.org airq = VERHOME + '/data/air_quality_no2.csv' air_quality = pd.read_csv ( airq , index_col=0, parse_dates=True) print (air_quality , '\n' ) import matplotlib.pyplot as plt air_quality.plot () ; plt.savefig ( DOT + '/air1.png' ) air_quality [ 'station_paris' ].plot() ; plt.savefig ( DOT + '/air2.png' ) air_quality.plot.scatter ( x='station_london' , y='station_paris', alpha=0.5 ) ; plt.savefig ( DOT + '/air3.png' ) air_quality.plot.box () ; plt.savefig ( DOT + '/air4.png' ) air_quality.plot.area ( figsize = ( 12 , 4) , subplots=True ) ; plt.savefig ( DOT + '/air5.png' ) #------------------------------------------------#-------------------------------------------# def generate_documentation () : print ( '\n* generate_documentation' ) from pydoc import writedoc from os import chdir import zorro as zormod chdir (DOT) # change back print ( '\n* generate_documentation' ) writedoc (zormod) from zorro import delete_nlines delete_nlines ( 6 , 8 , DOT + '/zorro.html' ) # delete lines 6 line from line number 8 #------------------------------------------------#-------------------------------------------# main () # goto to "main" and never return print ( 'ERROR: sentinel after main' ) #------------------------------------------------#-------------------------------------------# ''' Notices and documentation title:Vereda description:A path through Python with code snippets version:1 date:2023-11-01 relation:Zorro creator:M.T. Carrasco Benitez rights:CC BY-SA - Creative Commons Attribution-ShareAlike ''' ##