Python String Literals

Some times while dealing with strings using python we find that a string starts with a character before the string quotes. for example:

r'here is my string' 

or:

u'here is another string'

what are the 'r' and 'u'??

In python strings, we may use the backslash (\) character to escape characters that has different meanings such as:

• New Line (\n)
• Tab (\t)
• backslash it self (\\) :)
• ...etc

Also strings may optionally be prefixed with a letter - like the examples above - and here are there different meanings:

• A prefix letter 'r' or 'R', these strings are called "Raw Strings" and they use different rules for the backslash skipping rule ...
• All characters following the backslash are included in the string as they are. For example "\n" is not a new line ... it is a backslash followed by a small character 'n'. Also, "\"" will give a string error because the backslash followed by a double quotes is interpreted as they are and hence, this string contains three double quotes and this is invalid. 
• Also if a single backslash followed by a newline is interpreted as two characters as a part of the string, not as a line continuation !!

• A prefix letter 'u' or 'U' makes it a "Unicode String" which used the Unicode character set defined by the Unicode Consortium ISO 10646.
• Here the backslash only escape the codes for characters. Let's see examples:
• u"\u0062" is a small letter 'b'.
• u"\u0025" is the percentage sign '%'
• u"\n" here the backslash will not escape the new line character and the string will remain as it is "\n"  

Hope this was useful :)