mediter

rails db:rollback STEP=1

# Is a way to do this, if the migration you want to rollback is the last one applied. You can substitute 1 for however many migrations you want to go back.

# For example:

rails db:rollback STEP=5
# Will also rollback all the migration that happened later (4, 3, 2 and also 1).

# In order to rollback a specific migration use:

mediter

+__rvm_make:0> make -j 1
	CC = gcc
	LD = ld
	LDSHARED = gcc -dynamiclib
	CFLAGS = -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -Wdivision-by-zero -Wdeprecated-declarations -Wextra-tokens   -fno-common -pipe 
	XCFLAGS = -D_FORTIFY_SOURCE=2 -fstack-protector -fno-strict-overflow -fvisibility=hidden -DRUBY_EXPORT
	CPPFLAGS = -I/usr/local/opt/libyaml/include -I/usr/local/opt/readline/include -I/usr/local/opt/libksba/include -I/usr/local/opt/openssl/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT   -I. -I.ext/include/x86_64-darwin17 -I./include -I.
	DLDFLAGS = -Wl,-undefined,dynamic_lookup -Wl,-multiply_defined,suppress -L/usr/local/opt/libyaml/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libksba/lib -L/usr/local/opt/openssl/lib -install_name /Users/jun/.rvm/rubies/

mediter

# you can call #sum iterator on it:

numbers = [1, 2, 3, 4, 5]

numbers.sum
# => 15


# N.B: In Ruby versions < 2.4, sum didn't exist. The idiomatic way to get the same result was with #reduce:

mediter

https://stackoverflow.com/a/30404532

As of Swift 4 (Xcode 9), the Swift standard library provides methods to convert between Swift string ranges (Range<String.Index>) and NSString ranges (NSRange). Example:

let str = "a👿b🇩🇪c"
let r1 = str.range(of: "🇩🇪")!

// String range to NSRange:
let n1 = NSRange(r1, in: str)
print((str as NSString).substring(with: n1)) // 🇩🇪