我有一个对象列表，其中包含交易媒介和交易金额。我想查找特定交易的总金额。
例如- 我在列表中有以下对象-
Credit card 10
Debit card 20
Credit card 30
Credit card 20
Debit card 20
Digital Wallet 30
Debit card 40
我想要这样的输出-
Credit Card 60
Debit card 80
Digital Wallet 30
我希望它使用Java 8流来完成。谁能帮忙！
答案 0 :(得分：1)
您可以这样做
groupingBy首先使用function NoOptionsMessage(props) {
return (
<Typography
color="textSecondary"
className={props.selectProps.classes.noOptionsMessage}
{...props.innerProps}
>
{props.children}
</Typography>
);
}
function inputComponent({ inputRef, ...props }) {
return <div ref={inputRef} {...props} />;
}
function Control(props) {
////console.dir(props.selectProps.inputValue); i am able to get the user input here
// so i was thinking i can call my reducer somewhere here but no luck
// my function is passed from my parent component so i wish to call this.props.theFunction here
return (
<TextField
fullWidth
InputProps={{
inputComponent,
inputProps: {
className: props.selectProps.classes.input,
ref: props.innerRef,
children: props.children,
...props.innerProps,
},
}}
onChange={(e) => IntegrationReactSelect.testing(e)}
/>
);
}
function Option(props) {
return (
<MenuItem
buttonRef={props.innerRef}
selected={props.isFocused}
component="div"
style={{
fontWeight: props.isSelected ? 500 : 400,
}}
{...props.innerProps}
>
{props.children}
</MenuItem>
);
}
function Placeholder(props) {
return (
<Typography
color="textSecondary"
className={props.selectProps.classes.placeholder}
{...props.innerProps}
>
{props.children}
</Typography>
);
}
function SingleValue(props) {
return (
<Typography className={props.selectProps.classes.singleValue} {...props.innerProps}>
{props.children}
</Typography>
);
}
function ValueContainer(props) {
return <div className={props.selectProps.classes.valueContainer}>{props.children}</div>;
}
function MultiValue(props) {
return (
<Chip
tabIndex={-1}
label={props.children}
className={classNames(props.selectProps.classes.chip, {
[props.selectProps.classes.chipFocused]: props.isFocused,
})}
onDelete={event => {
props.removeProps.onClick();
props.removeProps.onMouseDown(event);
}}
/>
);
}
const components = {
Option,
Control,
NoOptionsMessage,
Placeholder,
SingleValue,
MultiValue,
ValueContainer
};
class IntegrationReactSelect extends React.Component {
state = {
single: null,
multi: null,
};
handleChange = name => value => {
this.setState({
[name]: value,
});
this.props.getSelectMultipleValue(value);
};
render() {
const { classes } = this.props;
return (
<div className={classes.root}>
<Select
classes={classes}
options={this.props.theUserFromParentComponent}
components={components}
value={this.state.multi}
onChange={this.handleChange('multi')}
placeholder={this.props.reactSelectName}
isMulti
/>
</div>
);
}
}
收集器按其媒介对交易进行分组。然后使用下游收集器对每个组的交易金额求和。