• ascii, unicode, utf-8
• Unicode & Javascript, history of UCS-2 w/ UTF16

{% highlight python %}

!/usr/bin/env python

-- coding: utf-8 --

Ascii Tools

ord('A') 65 chr(65) 'A' {% endhighlight %}

Declaration & Initialization

{% highlight java %} // Java String demoA = null; String demoB = ""; {% endhighlight %}

{% highlight python %}

python

Prefer using single quote for char

demoA = 'It\'s a demo A.'

Prefer using double quote for string to align with other language

demoB = "It\'s a demo B." chinese = "中文" #utf-8 uchinese = u"中文" #unicode

demoC = """ It's a ... demo ... C ... """ demoC " It's a \ndemo \nC\n" r"It\'s demo" "It\'s demo" type(demoA) del demoC {% endhighlight %}

{% highlight go %} // Go var demoA string; demoB := "It's a demoB" {% endhighlight %}

{% highlight javascript %} // Javascript var demoStr = "demo string" var demoStr1 = 'demo string' // signle quote var demoStr = "demo string" // double quote var demoChar = 'a' // no char type in JS, use sigle character in string to present char var demoPath = "\/home\/kasper" // escape

var demoUnicode = '\u4e2d\u6587'; // unicode '中文'

ES6 - multi-line - ... This is multi-line string {% endhighlight %}

Operations

{% highlight java %} === encoding === // java System.getProperties().getProperty("file.encoding") {% endhighlight %}

{% highlight python %}

python

sys.getdefaultencoding() sys.setdefaultencoding("utf-8") encode(arg1) # encode to specific encoding arg1, e.g. "utf-8", "gb2312" decode() # -> unicode

basic operations

python

"a" + "b", "-".join(["a", "b", "c"]) "a-b-c".split("-"), "a\nb\nc".splitlines() or splitlines(True) startwith(), endwith() lower(), upper() strip(), lstrip(), rstrip() replace(), find

"a" * 3 'aaa'

{% endhighlight %}

{% highlight go %} // go str1 + str2 // string concatination len(s) // get length of string str1[i] // get char from string for i, ch := range str { ... } {% endhighlight %}

{% highlight javascript %} // Javascript str1 = '\u0041' // or double quota "\u0041" str1 += str2; str.length // string length is attribute. In Java, length() is method str.toUpperCase() str1 === str2 str2[0] // 'H' str2.indexOf('World') // 6 str2.substring(0, 5); // Hello, range not include 5 str2.substring(6); // World {% endhighlight %}

format

{% highlight java %} // java

{% endhighlight %}

{% highlight python %}

python

support as format in C

%[(key)][flags(-(left alignment)/+/#(i.e. #c, #X) etc)][width][.precision]typecode(d/f/s/x etc)

%% uses for '%' escape

"%(key)s=%(value)d" % dict(key = "a", value = 10) 'a=10'

format for container objects: list, dict

{field!convertflag:formatspec: [[fill]align][sign][#][0][width][.precision][typecode]}

"test {demo}".format(demo="Kasper") 'test Kasper'

{% endhighlight %}

{% highlight go %} // go // %d, %f, %s, %x, %c fmt.Printf("The length of \"%s\" is %d \n", str, len(str))

{% endhighlight %}

hex(id(x)) - return obj id - memory address