1FORMATSTR(3) formatstr 1.5 FORMATSTR(3)
2
6 formatstr - String Formatter object
7
9 Object used to format base objects into strings. It extends the func‐
10 tionality of the string Formatter object to include new modifiers for
11 different objects. Some of these new modifiers include conversion of
12 strings into a sequence of hex characters, conversion of strings to
13 their corresponding CRC32 or CRC16 representation.
14
16 class FormatStr(string.Formatter)
17 String Formatter object
18 FormatStr() -> New string formatter object
20 Usage:
22 from formatstr import FormatStr
23 x = FormatStr()
25 out = x.format(fmt_spec, *args, **kwargs)
27 out = x.vformat(fmt_spec, args, kwargs)
28 Arguments should be surrounded by curly braces {}, anything that is
30 not contained in curly braces is considered literal text which is
31 copied unchanged to the output.
32 Positional arguments to be used in the format spec are specified
33 by their index: {0}, {1}, etc.
34 Named arguments to be used in the format spec are specified by
35 their name: {name1}, {name2}, etc.
36 Modifiers are specified after the positional index or name preceded
38 by a ":", "{0:#x}" -- display first positional argument in hex
39 Examples:
41 # Format string using positional arguments
42 out = x.format("{0} -> {1}", a, b)
43 # Format string using named arguments
45 out = x.format("{key}: {value}", key="id", value=32)
46 # Format string using both positional and named arguments
48 out = x.format("{key}: {value}, {0}, {1}", a, b, key="id", value=32)
49 # Use vformat() method instead when positional arguments are given
51 # as a list and named arguments are given as a dictionary
52 # The following examples show the same as above
53 pos_args = [a, b]
54 named_args = {"key":"id", "value":32}
55 out = x.vformat("{0} -> {1}", pos_args)
56 out = x.vformat("{key}: {value}", named_args)
57 out = x.vformat("{key}: {value}, {0}, {1}", pos_args, named_args)
58 # Display string in hex
60 out = x.format("{0:x}", "hello") # out = "68656c6c6f"
61 # Display string in hex with leading 0x
63 out = x.format("{0:#x}", "hello") # out = "0x68656c6c6f"
64 # Display string in crc32
66 out = x.format("{0:crc32}", "hello") # out = "0x3610a686"
67 # Display string in crc16
69 out = x.format("{0:crc16}", "hello") # out = "0x9c62"
70 # Substring using "@" format modifier
72 # Format {0:@sindex[,eindex]} is like value[sindex:eindex]
73 # {0:@3} is like value[3:]
74 # {0:@3,5} is like value[3:5]
75 # {0:.5} is like value[:5]
76 out = x.format("{0:@3}", "hello") # out = "lo"
77 out = x.format("{0:.2}", "hello") # out = "he"
78 # Conditionally display the first format if argument is not None,
80 # else the second format is displayed
81 # Format: {0:?format1:format2}
82 out = x.format("{0:?tuple({0}, {1})}", 1, 2) # out = "tuple(1, 2)"
83 out = x.format("{0:?tuple({0}, {1})}", None, 2) # out = ""
84 # Using 'else' format (including the escaping of else character):
85 out = x.format("{0:?sid{0}:NONE}", 5) # out = "sid:5"
86 out = x.format("{0:?sid{0}:NONE}", None) # out = "NONE"
87 # Nested formatting for strings, where processing is done in
89 # reversed order -- process the last format first
90 # Format: {0:fmtN:...:fmt2:fmt1}
91 # Display substring of 4 bytes as hex (substring then hex)
92 out = x.format("{0:#x:.4}", "hello") # out = "0x68656c6c"
93 # Display first 4 bytes of string in hex (hex then substring)
94 out = x.format("{0:.4:#x}", "hello") # out = "0x68"
95 # Integer extension to display umax name instead of the value
97 # Format: {0:max32|umax32|max64|umax64}
98 # Output: if value matches the largest number in format given,
99 # the max name is displayed, else the value is displayed
100 out = x.format("{0:max32}", 0x7fffffff) # out = "max32"
101 out = x.format("{0:max32}", 35) # out = "35"
102 # Number extension to display the value with units
104 # Format: {0:units[.precision]}
105 # Output: display value as a string with units, by default
106 # precision=2 and all trailing zeros are removed.
107 # To force the precision use a negative number.
108 out = x.format("{0:units}", 1024) # out = "1KB"
109 out = x.format("{0:units.4}", 2000) # out = "1.9531KB"
110 out = x.format("{0:units.-2}", 1024) # out = "1.00KB"
111 # Date extension for int, long or float
113 # Format: {0:date[:datefmt]}
114 # The spec given by datefmt is converted using strftime()
115 # The conversion spec "%q" is used to display microseconds
116 # Output: display value as a date
117 stime = 1416846041.521868
118 out = x.format("{0:date}", stime) # out = "Mon Nov 24 09:20:41 2014"
119 out = x.format("{0:date:%Y-%m-%d}", stime) # out = "2014-11-24"
120 # List format specification
122 # Format: {0[[:listfmt]:itemfmt]}
123 # If one format spec, it is applied to each item in the list
124 # If two format specs, the first is the item separator and
125 # the second is the spec applied to each item in the list
126 alist = [1, 2, 3, 0xffffffff]
127 out = x.format("{0:umax32}", alist) # out = "[1, 2, 3, umax32]"
128 out = x.format("{0:--:umax32}", alist) # out = "1--2--3--umax32"
129 Methods defined here:
132 ---------------------
133 format_field(self, value, format_spec)
135 Override original method to include modifier extensions
136 get_value(self, key, args, kwargs)
138 Override original method to return "" when the positional argument
139 or named argument does not exist:
140 x.format("0:{0}, 1:{1}, arg1:{arg1}, arg2:{arg2}", a, arg1=11)
141 the {1} will return "" since there is only one positional argument
142 the {arg2} will return "" since arg2 is not a named argument
143
145 crc16(value)
146 Convert string to its crc16 representation
147 crc32(value)
149 Convert string to its crc32 representation
150 hexstr(value)
152 Convert string to its hex representation
153 int_units(value)
155 Convert string value with units to an integer
156 value: String to convert
159 Examples:
161 out = num_units("1MB") # out = 1048576
163 str_time(value)
164 Convert the number of seconds to a string with a format of "[h:]mm:ss"
165 value: Time value to convert (in seconds)
168 Examples:
170 out = str_time(123.0) # out = 02:03
172 out = str_time(12345) # out = 3:25:45
173 str_units(value, precision=2)
174 Convert number to a string value with units
175 value: Number to convert
178 precision:
180 Return string value with the following floating point
181 precision. By default no trailing zeros are returned but
182 if the precision is given as a negative number the preci‐
183 sion is enforced [default: 2]
184
186 No known bugs.
187
189 Jorge Mora (mora@netapp.com)
190NFStest 2.1.5 14 February 2017 FORMATSTR(3)