inject:into: in Smalltalk

The fold: thread a running value through a collection.

"inject:into: is the fold: thread a running value through."
| sheets total longest |
sheets := #(120 340 85 500 210).

total := sheets inject: 0 into: [:sum :n | sum + n].
Transcript show: 'Edition total: ', total printString; cr.

longest := sheets inject: 0 into: [:best :n | best max: n].
Transcript show: 'Largest run: ', longest printString; cr.

"The accumulator can be anything -- here a string."
Transcript show: (#('set' 'proof' 'print')
    inject: 'plan' into: [:acc :step | acc, ' > ', step]); cr.

How it works

1. The first argument seeds the accumulator.
2. The block receives the running value and each element.
3. Any object can accumulate — numbers or strings alike.

Keywords and builtins used here

• Transcript
• cr
• printString

The run, in numbers

Lines

13

Characters to type

505

Tokens

94

Three-star pace

55 tpm

At the three-star pace of 55 tokens a minute, this run takes about 103 seconds.

Type this snippet

Step 2 of 4 in Enumeration, step 15 of 31 in Language basics.

← Previous Next →