How do I fix Invalid first data argument ?
显示 更早的评论
Here's my code. Matlab said there's an error using plot. Please help!
plot ('TBC,theta')
hold on
plot ('TAB, theta')
hold off
grid on
table('TAB & TBC versus theta')
xlabel('theta/ radians');
ylabel ('TAB &TBC /lb');
采纳的回答
Les Beckham
2018-2-3
0 个投票
The plot() function requires variables as arguments, not a character vector (which is what you have created by putting single quotes around the arguments). Assuming that TBC, TAB, and theta are existing variables in your workspace with consistent dimensions, the plot() commands should work if you take off the single quotes. Also, I think you might mean title() instead of table() on line 6.
更多回答（1 个）
JOb
2025-12-1
编辑：Walter Roberson
2025-12-1
I have the same question but different:
%% 5. Plot – alle rondes
figure;
plot('laps,lap_times_in_sec'; '-0' 'LineWidth'; 1.5;)
xlabel("Lap number");
ylabel("Lap time (s)");
title("Lap times vs. laps – All tires, All cars");
grid on;
When I run this script I get the following error:
File: Script_Portfolio_blok1.m Line: 47 Column: 28
Invalid expression. When calling a function or indexing a variable, use
parentheses. Otherwise, check for mismatched delimiters.
1 个评论
Walter Roberson
2025-12-1
plot() expects one of the following as a first parameter:
- a Y value of type single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | categorical | datetime | duration
- an X value of type single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | categorical | datetime | duration
- (seldom, but permitted) a name/value pair
'laps,lap_times_in_sec' is not any of the permitted types, and is also not a valid name for name/value pairs.
Furthermore, parameters to plot() must be separated with commas, not with spaces and not with semi-colons.
The '-0' part looks like an attempt to specify a linespec, However, there is no valid linespec that includes '0' .
I suspect that what you want is
plot(laps, lap_times_in_sec, '-o', 'LineWidth', 1.5)
类别
在 帮助中心 和 File Exchange 中查找有关 Line Plots 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
