Python Input and Output Output Formatting Two methods to format output 1 Perform all string formatting yourself 2 Use the str format method Converting Values to Strings Use either the str or repr functions str will return a human readable representation repr will return representations that may be read from the interpreter If str is not defined for a given object str will return the same value as repr str and repr s hello world n print str s hello world print repr s hello world n Justifications rjust will right justify a string of a given width and pad it with spaces on the lef rjust example for x in range 1 6 print repr x rjust 1 print repr x x rjust 2 print repr x x x rjust 3 1 1 1 2 4 8 3 9 27 4 16 64 5 25 125 Other Similar Methods ljust for lef justification center for center justification zfill will pad a numeric string with 0 s on the lef example of zfill 13 zfill 5 00013 13 zfill 5 0013 str format print This 0 uses format 1 format string fields This string uses format fields print This food is adjective format food spam adjective great This spam is great s and r Use s inside brackets to apply str to the value before it is formatted Use r to apply repr Additional Formatting Use following the field name for additional formatting For example to truncate Pi to three places print PI is about 0 3f format math pi PI is about 3 142 An integer afer the will cause the field to be a minimum number of characters wide table x 120 y 121 z 122 for char value in table items print 0 10 1 10d format char value x 120 y 121 z 122 Reading and Writing Files open returns a file object Commonly called with two arguments 1 filename 2 mode f open temp myfile w close closes a file freeing up system resources Modes Mode string Description r Read only default if not specified w Writing will erase existing file with same name a Append r Reading and Writing Reading filename read size read and return a specified number of bytes filename read read the entire file filename readline reads a single line from the file keeps the n at the end unless the end of file has been reached filename readlines returns a list containing each line in the file Writing filename write string writes the contents of the string to the file must convert non string values to strings first with either str or repr Other File Methods filename tell returns an integer representing the current position in the file measured in bytes from the beginning of the file filename seek offset from what computes a position by adding the offset to a reference point from what from what may have 1 of 3 values from what Description 0 Beginning of file default 1 Current position 2 End of file use a negative offset Any Questions Reference http docs python org tutorial inputoutput html
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