python – sebuah catatan online..

Syntax personal notes (Python)

Content

NoteCode	Purpose	Syntax	Additional Information
?AN001	Dealing with Japanese character /format [String encoding]	QtCore.QString.fromUtf8	Library: PySide Keyword: try, except, AttributeError, def, UTF8 Encoding, string encoding
AN002	Using Japanese character inside the source file (.py) [File encoding]	# -- coding: utf-8 --	Keyword: file encoding, UTF8
AN002	Print without newline	from __future__ import print_function	Keyword: __future__ , print statement, print() function, Python 3, Python 2.6, end

AN001
Purpose: Dealing with Japanese character /format [String encoding]
Library: PySide (using QtCore)
Keyword: try, except, AttributeError, def, UTF8 Endoding, string encoding

What is
UTF8 Encoding: Unicode Transformation Format, that uses 8-bit blocks to represent characters

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    def _fromUtf8(s):
        return s

Code location: at the beginning (header)

AN002
Purpose: Using Japanese character inside the source file (.py) [File encoding]
Keyword: file encoding, UTF8

# -*- coding: utf-8 -*-

Code location: at the VERY beginning (header)

AN003
Purpose: Print without newline
Keyword: __future__ , print statement, print() function, Python 3, Python 2.6, end

Currently & previously (before Python 3):
print is a statement, and the resulted printed text always end with newline (or whitespace, if print command is ended with comma ‘,’)
After Python 3:
print becomes function (instead of statement) print() and argument “end” can be used to specify the end of printed text
How to use print() if installed python version is still Python 2.6 (and above):
using code

from __future__ import print_function

print("\t", end="")

Libraries in Python

Useful modules, packages, and libraries in Python. This is a list of personal preferences (previously/currently used).
Some definitions are taken from here and here.

Purpose	Modules name	Additional information
GUI	TkInter	Traditional python UI toolkit
	PyQt	Qt framework
	PySide	Qt framework QtGui QtCore
Foreign function interface	CTypes	Package for calling functions of dlls/shared libraries [now is included w/ Py2.5 as Standard Library ]
XML processing	ElementTree	[now is included w/ Py2.5 as Standard Library]
Database	sqlite3

Operating System services	os	miscellaneous OS interfaces [Standard Library]
	time	time access and conversions [Standard Library]
Text Processing services	re	Regular expression [Standard Library]
Numeric & Mathematical modules	math	mathematical functions [Standard Library]
Data types	copy	shallow & deep copy operations [Standard Library]
Structured Markup processing tools	xml.dom	XML processing, Document Object Model (DOM) API [Standard Library]
	xml.dom.minidom	minimal DOM implementation [Standard Library]
Binary Data Services	codecs	Codec registry and base classes [Standard Library]
3D-rendering related	pivy	python binding library for Coin3D (3D-rendering library)
Read/write office files	openpyxl	to read/write Ecxel 2010 files [stored in PyPackageIndex]

CMD command, python related

Berikut ini daftar perintah cmd yang berhubungan dengan python

Purpose	Command	Additional Information
Installing pip (python install manager)	python get-pip.py	From cmd & directory where you save get-pip.py
	pip install	–
	where pip	if “pip install” results error, check whether pip command refer to other program, e.g., strawberry perl (if yes, then uninstall strawberry perl)
Checking which python is associated with (if accidentally installed 2 version of python)	assoc .py	probable output: .py=Python.File
	ftype Python.File	probable output: Python.File=”C:\…\python.exe” “%1” %*
Installing in specific target (e.g., other directory inside specific package)	pip install –target=”/Applications/FreeCAD.app/Contents/lib/python2.6/site-packages” openpyxl	*belum berhasil nyoba di FCAD
Installing pyside	pip install pyside
To convert .ui (pyside) into .py, using pyside-uic (converter provided by pyside)	pyside-uic NAMEOFUIFILE -o NAMEOFPYFILE -x	pyside-uic is located in folder: python Lib\site-packages\PySide switch -x: if you want to double-click the resulted .py
Help	python –help	help: list of options/switches/parameters
Python version	python –version
	python -V

XML to tab

Print as transpose if data is too wide to view from left to right.

Python, regex experiment.

# -*- coding: utf-8 -*-
from __future__ import print_function
import sys
import re
# xml2Tab_t.py drill4Opseq.xml 20 ProductData Machine MachiningData SequenceOperation > hasil.txt

# note:
# NOf = NumberOf
# [0]funtionName, [1]XML, [2]maxNumOfColumn, [3]wantedTag

minNOfArgv = 3
maxNOfColumn = int(sys.argv[minNOfArgv-1])

# --------------------------------

def printAs(type, line):
    if type=="title":
        doPrint("\s", "=", line)
    elif type=="data":
        doPrint("\"", "\"",  line)

def storeAs(dType, tType, line, array):
    if dType=="title":
        line = re.sub(r"^\s+", "", line)
        beg = "\s"
        en = "="        
    elif dType=="data":
        beg = "\""
        en = "\""

    reg = beg + r"(.*?)" + en
    i=0
    j=0

    if tType!="transpose" and tType!="normal":
        nResult = len(re.findall(reg, line, re.S))
        if nResult < maxNOfColumn:
            if nResult!=0:
                tType="normal"            
        else:
            tType="transpose"          
                
    for match in re.finditer(reg, line, re.S):        
        if tType=="transpose":            
            if dType=="title":
                array.append([]) #
                array[i].append(match.group(1))
                i=i+1
            elif dType=="data":
                array[i].append(match.group(1))
                i=i+1
        elif tType=="normal":
            if dType=="title":
                if len(array)==0:
                    array.append([]) #
                array[0].append(match.group(1))
            elif dType=="data":
                if i==0:
                    array.append([])
                    i=len(array)
                array[i-1].append(match.group(1))            
def doPrint(beg, en, line):    
    reg = beg + r"(.*?)" + en
        
    "remove whitespace @beg.of line, esp. for title"
    line = re.sub(r"^\s+", "", line)

    if re.search(reg, line):  #biar bisa \n di luar for loop
            "print substring between beg and end"
        for match in re.finditer(reg, line, re.S):
            print(match.group(1), end="")
            print("\t", end="")
        print("")

def printArray(type, array):     
    for i in xrange(0, len(array)):
        for j in xrange(0, len(array[i])):
            print(str(array[i][j]), end="")
            print("\t", end="")
        print("")
    print("")

def main():    
    iLine = 0              # index line
    cArg = 0               # current (observed) argument
    insideTag = False
    aData = []
    
    if len(sys.argv) < minNOfArgv + 1:
        # note: sys.argv[0] is function name
        return    
        fo = open(sys.argv[1])    
    for sLine in fo:
        
        "check boundary (e.g., tag "
        for a in xrange(0, len(sys.argv) - minNOfArgv):
            reg = r"\<" + sys.argv[a + minNOfArgv]
            if re.search(reg, sLine):
                insideTag = True
                cArg = a
                iLine=1                
            reg = r"\<\/" + sys.argv[a + minNOfArgv]
            if re.search(reg, sLine):
                insideTag = False
                if sys.argv[cArg + minNOfArgv]=="ProductData":
                    print("")
                else:
                    print("<" + sys.argv[cArg + minNOfArgv]+">")
                    printArray("", aData)

        "get data"
        if insideTag:
            if sys.argv[cArg + minNOfArgv]=="ProductData":
                if iLine==2:
                    print("<"+sys.argv[cArg + minNOfArgv]+">")
                    printAs("title", sLine)
                    printAs("data", sLine)
                    print("")
                elif iLine==3:
                    printAs("title", sLine)
                    printAs("data", sLine)
                else:
                    printAs("data", sLine)
            else:
                if iLine==2:
                    aData[:]=[]
                    storeAs("title", "", sLine, aData)
                    storeAs("data", "", sLine, aData)
                else:
                    storeAs("data", "", sLine, aData)
                    
            iLine = iLine + 1    
    fo.close()    

if __name__ == "__main__":
    main()

Posting code to wordpress

Python, regex

Add <pre> in the beginning of the code
Add </pre> at the very end of the code
If indentation is needed, use  
In this case, 4 backspace is converted into 4  
(because double tab doesn’t seem working)

.bat (double click)

main.py wantedCode > result.txt

main.py

# -*- coding: utf-8 -*-
from __future__ import print_function
import sys
import re

def main():
    i = 0
    fh = open(sys.argv[1])    
    for line in fh:        	
	if i==0:
            print("<pre>", end="")
        line = re.sub(r"\s\s\s\s", "    ", line)
        #line = re.sub("    ", "\t", line)
        print(line, end="")
        i=i+1        

    print("</pre>", end="")
    fh.close()    

if __name__ == "__main__":
    main()

Additional:

HTML	Seen
print(“<pre>”, end=””)	print(“<pre>”, end=””)
print(“</pre>”, end=””)	print(“</pre>”, end=””)

Print inside tag XML

Regex, python

1. interface .bat (double click), e.g., execute.bat

main.py drill4Opseq.xml tag1 tag2 > hasil.txt

2. python script, e.g., main.py

# -*- coding: utf-8 -*-
from __future__ import print_function
import sys
import re

def printData(beg, en, line):    
    reg = beg + r"(.*?)" + en
        
    "remove whitespace @beg.of line, esp. for title"
    line = re.sub(r"^\s+", "", line)

    if re.search(reg, line):    
        "print substring between beg and end"
        for match in re.finditer(reg, line, re.S):
            print(match.group(1), end="")
            print("\t", end="")
        print("")

def main():
    i = 0
    arg = 0
    insideTag = False
    #app = QtGui.QApplication(sys.argv)
    if len(sys.argv)")
                printData("\s", "=", line)
            printData("\"", "\"",  line)
            i=i+1
    fh.close()    

if __name__ == "__main__":
    main()

ps: pakai   buat indent 😀

Regex with Python

Expression:

between double quote
to mark regex as raw string, use r in front of expression, such as
```
r"^a.*\.html$"
```
this way, no need to use \\

Contents:

Frequently used command
Metacharacters
Example inside character class []
General example
Special sequences

1. FREQUENTLY USED COMMAND:

No	Command	Title
1	re.search(expression, substring)	match expression in a substring
		re.search(“cat”, “a cat and a rat can’t be friends”)
2	re.match(expression, substring)	match ONLY in the BEGINNING of the string. This command is only in python (can’t be used in perl)
		print re.match(r”M[ae][iy]er”, “He is called Meyer”)
		returns None
3	re.MULTILINE or re.M	match also after newline
		s = s2 + "\n" + s1 print re.search(r"^M[ae][iy]er", s, re.MULTILINE)
		returns None

2. METACHARACTERS

A metacharacter = a character that has special meaning

Metacharacter	Meaning
[]	Character class, means either, if any
^	Caret, means negation (but/except), only if it is used directly after [
.	any character (wildcard? biasanya pakai *)
*	asterisk or star, means that this subexpression may be repeated arbitrarily (including 0 times)
^	matches the start of the string
^	re.search(r"^M[ae][iy]er", "Mayer is a very common name")
$	matches the end of the string (or just before newline if its in MULTILINE mode)
$	e.g., re.search(r"Python\.$","I like Python and Perl.")

* usually, metacharacters should be preceded by a backslash in order to drop their special meaning, and be treated literally inside an expression

3. EXAMPLE INSIDE CHARACTER CLASS []

Expression	Meaning
[ae]	either a or e
r”M[ae][iy]er”	either Maier, Mayer, Meier, or Meyer
[a-e]	[abcde]
[a-z]	[abc … z]
[-a-z]	[-abc … z], i.e., – o & between [abc … z]
[0-5]	[012345]
[A-Z]	any uppercase letter
[^abc]	anything but a, b, or c
[a^bc]	a, b, c, or ^
.at	any 3 letter words, ended by “at”

4. GENERAL EXAMPLE

Expression	Meaning
r”^a.*\.html$”	substring started with an a and end with .html
r”M[ae][iy]er”	either: Maier, Mayer, Meier, or Meyer
r”[a-zA-Z0-9_]”	all lowercase characters + uppercase characters + all digits + underscore
[a-z]	[abc … z]
[-a-z]	[-abc … z], i.e., – o & between [abc … z]
[0-5]	[012345]
[A-Z]	any uppercase letter
[^abc]	anything but a, b, or c
[a^bc]	a, b, c, or ^
.at	any 3 letter words, ended by “at”
r”M[ae][iy]e?r”	either: Maier, Mair, Mayer, Mayr, Meier, Meir Meyer, Meyr
r”[0-9]*”	any sequence of digits, even if its empty string

5. SPECIAL SEQUENCES

Expression	Meaning
\d	[0-9], any decimal digit
\D	complement of \d i.e., [^0-9], any non-digit characters
\s	[\t\n\r\f\v], whitespace characters
\S	complement of \s i.e., [^\t\n\r\f\v]
\w	[a-zA-Z0-9_], any alphanumeric characters
\W	complement of \w (symbols?)
\b	empty string, but only at the start or end of a word
\B	empty string, but NOT at the start or end of a word
\\	literal backslash
.at	any 3 letter words, ended by “at”

Contoh code (for personal use) [ps: how to add indent? #pythonProblem]

# -*- coding: utf-8 -*-
from __future__ import print_function
from PySide import QtCore, QtGui
import sys
import re 

def main(): 
    i = 1
    app = QtGui.QApplication(sys.argv)
    fh = open("analyzeMe.txt")
    #print str(i)
    for line in fh:
        if i==1:
        line = re.sub(r"^\s+", "", line)
        line = re.sub(r"\<MD", "", line) 
        
        for match in re.finditer(r'\s(.*?)=', line, re.S):
            print (match.group(1), end="")
            print ("\t", end="")
            print("")

        for match in re.finditer(r'"(.*?)"', line, re.S): 
        print (match.group(1), end="")
        print ("\t", end="")
        i=i+1
        print("")
    fh.close()
    #sys.exit(app.exec_())

if __name__ == "__main__":
 main()

References

Kapan2 dibaca