text stringlengths 0 444 |
|---|
---- |
# bad |
x == 0.1 |
x != 0.1 |
# good - using BigDecimal |
x.to_d == 0.1.to_d |
# good - not an actual float comparison |
x == Float::INFINITY |
# good |
(x - 0.1).abs < Float::EPSILON |
# good |
tolerance = 0.0001 |
(x - 0.1).abs < tolerance |
# Or some other epsilon based type of comparison: |
# https://www.embeddeduse.com/2019/08/26/qt-compare-two-floats/ |
---- |
=== Exponential Notation [[exponential-notation]] |
When using exponential notation for numbers, prefer using the normalized scientific notation, which uses a mantissa between 1 (inclusive) and 10 (exclusive). Omit the exponent altogether if it is zero. |
The goal is to avoid confusion between powers of ten and exponential notation, as one quickly reading `10e7` could think it's 10 to the power of 7 (one then 7 zeroes) when it's actually 10 to the power of 8 (one then 8 zeroes). If you want 10 to the power of 7, you should do `1e7`. |
|=== |
| power notation | exponential notation | output |
| 10 ** 7 | 1e7 | 10000000 |
| 10 ** 6 | 1e6 | 1000000 |
| 10 ** 7 | 10e6 | 10000000 |
|=== |
One could favor the alternative engineering notation, in which the exponent must always be a multiple of 3 for easy conversion to the thousand / million / ... system. |
[source,ruby] |
---- |
# bad |
10e6 |
0.3e4 |
11.7e5 |
3.14e0 |
# good |
1e7 |
3e3 |
1.17e6 |
3.14 |
---- |
Alternative : engineering notation: |
[source,ruby] |
---- |
# bad |
3.2e7 |
0.1e5 |
12e4 |
# good |
1e6 |
17e6 |
0.98e9 |
---- |
== Strings |
=== String Interpolation [[string-interpolation]] |
Prefer string interpolation and string formatting to string concatenation: |
[source,ruby] |
---- |
# bad |
email_with_name = user.name + ' <' + user.email + '>' |
# good |
email_with_name = "#{user.name} <#{user.email}>" |
# good |
email_with_name = format('%s <%s>', user.name, user.email) |
---- |
=== Consistent String Literals [[consistent-string-literals]] |
Adopt a consistent string literal quoting style. |
There are two popular styles in the Ruby community, both of which are considered good - single quotes by default and double quotes by default. |
NOTE: The string literals in this guide are using single quotes by default. |
==== Single Quote [[consistent-string-literals-single-quote]] |
Prefer single-quoted strings when you don't need string interpolation or special symbols such as `\t`, `\n`, `'`, etc. |
[source,ruby] |
---- |
# bad |
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